diff --git a/.github/mergeable.yml b/.github/mergeable.yml
index bf4c87862..9eeb3615c 100644
--- a/.github/mergeable.yml
+++ b/.github/mergeable.yml
@@ -5,22 +5,22 @@ mergeable:
     validate:
       - do: or
         validate:
-        - do: description
-          must_include:
-            regex: '#skip-changelog'
-        - do: and
-          validate:
-            - do: dependent
-              changed:
-                file: 'src/**'
-                required: ['CHANGELOG.md']
-            - do: dependent
-              changed:
-                file: 'deltachat-ffi/src/**'
-                required: ['CHANGELOG.md']
+          - do: description
+            must_include:
+              regex: "#skip-changelog"
+          - do: and
+            validate:
+              - do: dependent
+                changed:
+                  file: "src/**"
+                  required: ["CHANGELOG.md"]
+              - do: dependent
+                changed:
+                  file: "deltachat-ffi/src/**"
+                  required: ["CHANGELOG.md"]
     fail:
       - do: checks
-        status: 'action_required' 
+        status: "action_required"
         payload:
           title: Changelog might need an update
           summary: "Check if CHANGELOG.md needs an update or add #skip-changelog to the PR description."
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4000e7296..cf8185b22 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,28 +8,22 @@ on:
 
 env:
   RUSTFLAGS: -Dwarnings
-   
+
 jobs:
-
-  fmt:
-    name: Rustfmt
+  lint:
+    name: Rustfmt and Clippy
     runs-on: ubuntu-latest
+    env:
+      RUSTUP_TOOLCHAIN: 1.67.1
     steps:
       - uses: actions/checkout@v3
-      - run: cargo fmt --all -- --check
-
-  run_clippy:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - name: Install clippy
-        run: rustup toolchain install 1.67.1 --component clippy
+      - name: Install rustfmt and clippy
+        run: rustup toolchain install $RUSTUP_TOOLCHAIN --component rustfmt --component clippy
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@v2
+      - name: Run rustfmt
+        run: cargo fmt --all -- --check
       - name: Run clippy
-        env:
-          RUSTUP_TOOLCHAIN: 1.67.1
         run: scripts/clippy.sh
 
   docs:
@@ -69,73 +63,73 @@ jobs:
             python: 3.7
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@master
+      - uses: actions/checkout@master
 
-    - name: Install Rust ${{ matrix.rust }}
-      run: rustup toolchain install ${{ matrix.rust }}
-    - run: rustup override set ${{ matrix.rust }}
+      - name: Install Rust ${{ matrix.rust }}
+        run: rustup toolchain install ${{ matrix.rust }}
+      - run: rustup override set ${{ matrix.rust }}
 
-    - name: Cache rust cargo artifacts
-      uses: swatinem/rust-cache@v2
+      - name: Cache rust cargo artifacts
+        uses: swatinem/rust-cache@v2
 
-    - name: Check
-      run: cargo check --workspace --bins --examples --tests --benches
+      - name: Check
+        run: cargo check --workspace --bins --examples --tests --benches
 
-    - name: Tests
-      run: cargo test --workspace
+      - name: Tests
+        run: cargo test --workspace
 
-    - name: Test cargo vendor
-      run: cargo vendor
+      - name: Test cargo vendor
+        run: cargo vendor
 
-    - name: Install python
-      if: ${{ matrix.python }}
-      uses: actions/setup-python@v4
-      with:
-        python-version: ${{ matrix.python }}
+      - name: Install python
+        if: ${{ matrix.python }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python }}
 
-    - name: Install tox
-      if: ${{ matrix.python }}
-      run: pip install tox
+      - name: Install tox
+        if: ${{ matrix.python }}
+        run: pip install tox
 
-    - name: Build C library
-      if: ${{ matrix.python }}
-      run: cargo build -p deltachat_ffi --features jsonrpc
+      - name: Build C library
+        if: ${{ matrix.python }}
+        run: cargo build -p deltachat_ffi --features jsonrpc
 
-    - name: Run python tests
-      if: ${{ matrix.python }}
-      env:
-        DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
-        DCC_RS_TARGET: debug
-        DCC_RS_DEV: ${{ github.workspace }}
-      working-directory: python
-      run: tox -e lint,mypy,doc,py3
+      - name: Run python tests
+        if: ${{ matrix.python }}
+        env:
+          DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
+          DCC_RS_TARGET: debug
+          DCC_RS_DEV: ${{ github.workspace }}
+        working-directory: python
+        run: tox -e lint,mypy,doc,py3
 
-    - name: Build deltachat-rpc-server
-      if: ${{ matrix.python }}
-      run: cargo build -p deltachat-rpc-server
+      - name: Build deltachat-rpc-server
+        if: ${{ matrix.python }}
+        run: cargo build -p deltachat-rpc-server
 
-    - name: Add deltachat-rpc-server to path
-      if: ${{ matrix.python }}
-      run: echo ${{ github.workspace }}/target/debug >> $GITHUB_PATH
+      - name: Add deltachat-rpc-server to path
+        if: ${{ matrix.python }}
+        run: echo ${{ github.workspace }}/target/debug >> $GITHUB_PATH
 
-    - name: Run deltachat-rpc-client tests
-      if: ${{ matrix.python }}
-      env:
-        DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
-      working-directory: deltachat-rpc-client
-      run: tox -e py3,lint
+      - name: Run deltachat-rpc-client tests
+        if: ${{ matrix.python }}
+        env:
+          DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
+        working-directory: deltachat-rpc-client
+        run: tox -e py3,lint
 
-    - name: Install pypy
-      if: ${{ matrix.python }}
-      uses: actions/setup-python@v4
-      with:
-        python-version: 'pypy${{ matrix.python }}'
+      - name: Install pypy
+        if: ${{ matrix.python }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: "pypy${{ matrix.python }}"
 
-    - name: Run pypy tests
-      if: ${{ matrix.python }}
-      env:
-        DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
-        DCC_RS_TARGET: debug
-        DCC_RS_DEV: ${{ github.workspace }}
-      working-directory: python
-      run: tox -e pypy3
+      - name: Run pypy tests
+        if: ${{ matrix.python }}
+        env:
+          DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
+          DCC_RS_TARGET: debug
+          DCC_RS_DEV: ${{ github.workspace }}
+        working-directory: python
+        run: tox -e pypy3
diff --git a/.github/workflows/jsonrpc-client-npm-package.yml b/.github/workflows/jsonrpc-client-npm-package.yml
index a1c3b4b82..7d7f0145e 100644
--- a/.github/workflows/jsonrpc-client-npm-package.yml
+++ b/.github/workflows/jsonrpc-client-npm-package.yml
@@ -1,15 +1,14 @@
-name: 'jsonrpc js client build'
+name: "jsonrpc js client build"
 on:
   pull_request:
   push:
     tags:
-    - '*'
-    - '!py-*'
-
+      - "*"
+      - "!py-*"
 
 jobs:
   pack-module:
-    name: 'Package @deltachat/jsonrpc-client and upload to download.delta.chat'
+    name: "Package @deltachat/jsonrpc-client and upload to download.delta.chat"
     runs-on: ubuntu-18.04
     steps:
       - name: Install tree
@@ -18,7 +17,7 @@ jobs:
         uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: '16'
+          node-version: "16"
       - name: Get tag
         id: tag
         uses: dawidd6/action-get-tag@v1
@@ -69,9 +68,9 @@ jobs:
         if: steps.upload-preview.outcome == 'success'
         run: node ./node/scripts/postLinksToDetails.js
         env:
-         URL: preview/${{ env.DELTACHAT_JSONRPC_TAR_GZ }}
-         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-         MSG_CONTEXT: Download the deltachat-jsonrpc-client.tgz
+          URL: preview/${{ env.DELTACHAT_JSONRPC_TAR_GZ }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          MSG_CONTEXT: Download the deltachat-jsonrpc-client.tgz
       # Upload to download.delta.chat/node/
       - name: Upload deltachat-jsonrpc-client build to download.delta.chat/node/
         if: ${{ steps.tag.outputs.tag }}
diff --git a/.github/workflows/jsonrpc.yml b/.github/workflows/jsonrpc.yml
index de05f50d6..692150cd7 100644
--- a/.github/workflows/jsonrpc.yml
+++ b/.github/workflows/jsonrpc.yml
@@ -35,6 +35,10 @@ jobs:
           npm run test
         env:
           DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
+      - name: make sure websocket server version still builds
+        run: |
+          cd deltachat-jsonrpc
+          cargo build --bin deltachat-jsonrpc-server --features webserver
       - name: Run linter
         run: |
           cd deltachat-jsonrpc/typescript
diff --git a/.github/workflows/node-delete-preview.yml b/.github/workflows/node-delete-preview.yml
index ba698c846..447448cd1 100644
--- a/.github/workflows/node-delete-preview.yml
+++ b/.github/workflows/node-delete-preview.yml
@@ -7,26 +7,25 @@ on:
 
 jobs:
   delete:
-
     runs-on: ubuntu-latest
 
     steps:
-    - name: Get Pullrequest ID
-      id: getid
-      run: |
-        export PULLREQUEST_ID=$(jq .number < $GITHUB_EVENT_PATH)
-        echo "prid=$PULLREQUEST_ID" >> $GITHUB_OUTPUT
-    - name: Renaming
-      run: |
-        # create empty file to copy it over the outdated deliverable on download.delta.chat
-        echo "This preview build is outdated and has been removed." > empty
-        cp empty deltachat-node-${{ steps.getid.outputs.prid }}.tar.gz
-    - name: Replace builds with dummy files
-      uses: horochx/deploy-via-scp@v1.0.1
-      with:
-        user: ${{ secrets.USERNAME }}
-        key: ${{ secrets.SSH_KEY }}
-        host: "download.delta.chat"
-        port: 22
-        local: "deltachat-node-${{ steps.getid.outputs.prid }}.tar.gz"
-        remote: "/var/www/html/download/node/preview/"
+      - name: Get Pullrequest ID
+        id: getid
+        run: |
+          export PULLREQUEST_ID=$(jq .number < $GITHUB_EVENT_PATH)
+          echo "prid=$PULLREQUEST_ID" >> $GITHUB_OUTPUT
+      - name: Renaming
+        run: |
+          # create empty file to copy it over the outdated deliverable on download.delta.chat
+          echo "This preview build is outdated and has been removed." > empty
+          cp empty deltachat-node-${{ steps.getid.outputs.prid }}.tar.gz
+      - name: Replace builds with dummy files
+        uses: horochx/deploy-via-scp@v1.0.1
+        with:
+          user: ${{ secrets.USERNAME }}
+          key: ${{ secrets.SSH_KEY }}
+          host: "download.delta.chat"
+          port: 22
+          local: "deltachat-node-${{ steps.getid.outputs.prid }}.tar.gz"
+          remote: "/var/www/html/download/node/preview/"
diff --git a/.github/workflows/node-docs.yml b/.github/workflows/node-docs.yml
index a7c07e0d9..1cd1a60d4 100644
--- a/.github/workflows/node-docs.yml
+++ b/.github/workflows/node-docs.yml
@@ -9,26 +9,26 @@ jobs:
   generate:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+      - uses: actions/checkout@v3
 
-    - name: Use Node.js 16.x
-      uses: actions/setup-node@v3
-      with:
-        node-version: 16.x
+      - name: Use Node.js 16.x
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16.x
 
-    - name: npm install and generate documentation
-      run: |
-        cd node
-        npm i --ignore-scripts
-        npx typedoc
-        mv docs js
+      - name: npm install and generate documentation
+        run: |
+          cd node
+          npm i --ignore-scripts
+          npx typedoc
+          mv docs js
 
-    - name: Upload
-      uses: horochx/deploy-via-scp@v1.0.1
-      with:
-        user: ${{ secrets.USERNAME }}
-        key: ${{ secrets.KEY }}
-        host: "delta.chat"
-        port: 22
-        local: "node/js"
-        remote: "/var/www/html/"
+      - name: Upload
+        uses: horochx/deploy-via-scp@v1.0.1
+        with:
+          user: ${{ secrets.USERNAME }}
+          key: ${{ secrets.KEY }}
+          host: "delta.chat"
+          port: 22
+          local: "node/js"
+          remote: "/var/www/html/"
diff --git a/.github/workflows/node-package.yml b/.github/workflows/node-package.yml
index f0cb1cc09..b737ca00c 100644
--- a/.github/workflows/node-package.yml
+++ b/.github/workflows/node-package.yml
@@ -1,11 +1,10 @@
-name: 'node.js build'
+name: "node.js build"
 on:
   pull_request:
   push:
     tags:
-    - '*'
-    - '!py-*'
-
+      - "*"
+      - "!py-*"
 
 jobs:
   prebuild:
@@ -19,7 +18,7 @@ jobs:
         uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: '16'
+          node-version: "16"
       - name: System info
         run: |
           rustc -vV
@@ -74,7 +73,7 @@ jobs:
         uses: actions/checkout@v3
       - uses: actions/setup-node@v2
         with:
-          node-version: '16'
+          node-version: "16"
       - name: Get tag
         id: tag
         uses: dawidd6/action-get-tag@v1
@@ -152,8 +151,8 @@ jobs:
         if: steps.upload-preview.outcome == 'success'
         run: node ./node/scripts/postLinksToDetails.js
         env:
-         URL: preview/${{ env.DELTACHAT_NODE_TAR_GZ }}
-         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          URL: preview/${{ env.DELTACHAT_NODE_TAR_GZ }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       # Upload to download.delta.chat/node/
       - name: Upload deltachat-node build to download.delta.chat/node/
         if: ${{ steps.tag.outputs.tag }}
diff --git a/.github/workflows/node-tests.yml b/.github/workflows/node-tests.yml
index e0d557d42..73e8d0cc4 100644
--- a/.github/workflows/node-tests.yml
+++ b/.github/workflows/node-tests.yml
@@ -1,4 +1,4 @@
-name: 'node.js tests'
+name: "node.js tests"
 on:
   pull_request:
   push:
@@ -19,7 +19,7 @@ jobs:
         uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: '16'
+          node-version: "16"
       - name: System info
         run: |
           rustc -vV
@@ -59,7 +59,7 @@ jobs:
           npm run test
         env:
           DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
-          NODE_OPTIONS: '--force-node-api-uncaught-exceptions-policy=true'
+          NODE_OPTIONS: "--force-node-api-uncaught-exceptions-policy=true"
       - name: Run tests on Windows, except lint
         timeout-minutes: 10
         if: runner.os == 'Windows'
@@ -68,4 +68,4 @@ jobs:
           npm run test:mocha
         env:
           DCC_NEW_TMP_EMAIL: ${{ secrets.DCC_NEW_TMP_EMAIL }}
-          NODE_OPTIONS: '--force-node-api-uncaught-exceptions-policy=true'
+          NODE_OPTIONS: "--force-node-api-uncaught-exceptions-policy=true"
diff --git a/.github/workflows/repl.yml b/.github/workflows/repl.yml
index efad7558e..a3d391fe2 100644
--- a/.github/workflows/repl.yml
+++ b/.github/workflows/repl.yml
@@ -11,13 +11,13 @@ jobs:
     name: Build REPL example
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v3
+      - uses: actions/checkout@v3
 
-    - name: Build
-      run: cargo build -p deltachat-repl --features vendored
+      - name: Build
+        run: cargo build -p deltachat-repl --features vendored
 
-    - name: Upload binary
-      uses: actions/upload-artifact@v3
-      with:
-        name: repl.exe
-        path: 'target/debug/deltachat-repl.exe'
+      - name: Upload binary
+        uses: actions/upload-artifact@v3
+        with:
+          name: repl.exe
+          path: "target/debug/deltachat-repl.exe"
diff --git a/.github/workflows/upload-docs.yml b/.github/workflows/upload-docs.yml
index c624cb081..8f0ceb3c0 100644
--- a/.github/workflows/upload-docs.yml
+++ b/.github/workflows/upload-docs.yml
@@ -8,20 +8,18 @@ on:
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
-    - name: Build the documentation with cargo
-      run: |
-        cargo doc --package deltachat --no-deps
-    - name: Upload to rs.delta.chat
-      uses: up9cloud/action-rsync@v1.3
-      env:
-        USER: ${{ secrets.USERNAME }}
-        KEY: ${{ secrets.KEY }}
-        HOST: "delta.chat"
-        SOURCE: "target/doc"
-        TARGET: "/var/www/html/rs/"
-
+      - uses: actions/checkout@v3
+      - name: Build the documentation with cargo
+        run: |
+          cargo doc --package deltachat --no-deps
+      - name: Upload to rs.delta.chat
+        uses: up9cloud/action-rsync@v1.3
+        env:
+          USER: ${{ secrets.USERNAME }}
+          KEY: ${{ secrets.KEY }}
+          HOST: "delta.chat"
+          SOURCE: "target/doc"
+          TARGET: "/var/www/html/rs/"
diff --git a/.github/workflows/upload-ffi-docs.yml b/.github/workflows/upload-ffi-docs.yml
index 73fa07cb1..c230b715e 100644
--- a/.github/workflows/upload-ffi-docs.yml
+++ b/.github/workflows/upload-ffi-docs.yml
@@ -8,20 +8,18 @@ on:
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
-    - name: Build the documentation with cargo
-      run: |
-        cargo doc --package deltachat_ffi --no-deps
-    - name: Upload to cffi.delta.chat
-      uses: up9cloud/action-rsync@v1.3
-      env:
-        USER: ${{ secrets.USERNAME }}
-        KEY: ${{ secrets.KEY }}
-        HOST: "delta.chat"
-        SOURCE: "target/doc"
-        TARGET: "/var/www/html/cffi/"
-
+      - uses: actions/checkout@v3
+      - name: Build the documentation with cargo
+        run: |
+          cargo doc --package deltachat_ffi --no-deps
+      - name: Upload to cffi.delta.chat
+        uses: up9cloud/action-rsync@v1.3
+        env:
+          USER: ${{ secrets.USERNAME }}
+          KEY: ${{ secrets.KEY }}
+          HOST: "delta.chat"
+          SOURCE: "target/doc"
+          TARGET: "/var/www/html/cffi/"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d76ac2a1..72eb1eff8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,20 +3,34 @@
 ## Unreleased
 
 ### Changes
-- deltachat-rpc-client: use `dataclass` for `Account`, `Chat`, `Contact` and `Message` #4042
-- python: mark bindings as supporting typing according to PEP 561 #4045
-- retry filesystem operations during account migration #4043
+- use transaction in `Contact::add_or_lookup()` #4059
 - ability to send backup over network and QR code to setup second device #4007
 
+### Fixes
+- Start SQL transactions with IMMEDIATE behaviour rather than default DEFERRED one. #4063
+
+### API-Changes
+
+
+## 1.109.0
+
+### Changes
+- deltachat-rpc-client: use `dataclass` for `Account`, `Chat`, `Contact` and `Message` #4042
+
 ### Fixes
 - deltachat-rpc-server: do not block stdin while processing the request. #4041
   deltachat-rpc-server now reads the next request as soon as previous request handler is spawned.
-- enable `auto_vacuum` on all SQL connections #2955
+- Enable `auto_vacuum` on all SQL connections. #2955
+- Replace `r2d2` connection pool with an own implementation. #4050 #4053 #4043 #4061
+  This change improves reliability
+  by closing all database connections immediately when the context is closed.
 
 ### API-Changes
 
 - Remove `MimeMessage::from_bytes()` public interface. #4033
 - BREAKING Types: jsonrpc: `get_messages` now returns a map with `MessageLoadResult` instead of failing completely if one of the requested messages could not be loaded. #4038
+- Add `dc_msg_set_subject()`. C-FFI #4057
+- Mark python bindings as supporting typing according to PEP 561 #4045
 
 
 ## 1.108.0
diff --git a/Cargo.lock b/Cargo.lock
index f3a00cc69..285f69661 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -306,7 +306,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acee9fd5073ab6b045a275b3e709c163dd36c90685219cb21804a147b58dba43"
 dependencies = [
  "async-trait",
- "axum-core 0.2.9",
+ "axum-core",
  "base64 0.13.1",
  "bitflags",
  "bytes",
@@ -315,7 +315,7 @@ dependencies = [
  "http-body",
  "hyper",
  "itoa",
- "matchit 0.5.0",
+ "matchit",
  "memchr",
  "mime",
  "percent-encoding",
@@ -326,43 +326,7 @@ dependencies = [
  "sha-1",
  "sync_wrapper",
  "tokio",
- "tokio-tungstenite 0.17.2",
- "tower",
- "tower-http",
- "tower-layer",
- "tower-service",
-]
-
-[[package]]
-name = "axum"
-version = "0.6.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5694b64066a2459918d8074c2ce0d5a88f409431994c2356617c8ae0c4721fc"
-dependencies = [
- "async-trait",
- "axum-core 0.3.2",
- "base64 0.20.0",
- "bitflags",
- "bytes",
- "futures-util",
- "http",
- "http-body",
- "hyper",
- "itoa",
- "matchit 0.7.0",
- "memchr",
- "mime",
- "percent-encoding",
- "pin-project-lite",
- "rustversion",
- "serde",
- "serde_json",
- "serde_path_to_error",
- "serde_urlencoded",
- "sha1",
- "sync_wrapper",
- "tokio",
- "tokio-tungstenite 0.18.0",
+ "tokio-tungstenite",
  "tower",
  "tower-http",
  "tower-layer",
@@ -385,23 +349,6 @@ dependencies = [
  "tower-service",
 ]
 
-[[package]]
-name = "axum-core"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cae3e661676ffbacb30f1a824089a8c9150e71017f7e1e38f2aa32009188d34"
-dependencies = [
- "async-trait",
- "bytes",
- "futures-util",
- "http",
- "http-body",
- "mime",
- "rustversion",
- "tower-layer",
- "tower-service",
-]
-
 [[package]]
 name = "backtrace"
 version = "0.3.67"
@@ -441,12 +388,6 @@ version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
 
-[[package]]
-name = "base64"
-version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ea22880d78093b0cbe17c89f64a7d457941e65759157ec6cb31a31d652b05e5"
-
 [[package]]
 name = "base64"
 version = "0.21.0"
@@ -1055,7 +996,7 @@ checksum = "23d8666cb01533c39dde32bcbab8e227b4ed6679b2c925eba05feabea39508fb"
 
 [[package]]
 name = "deltachat"
-version = "1.108.0"
+version = "1.109.0"
 dependencies = [
  "ansi_term",
  "anyhow",
@@ -1069,6 +1010,7 @@ dependencies = [
  "bitflags",
  "chrono",
  "criterion",
+ "crossbeam-queue",
  "deltachat_derive",
  "email",
  "encoded-words",
@@ -1096,8 +1038,6 @@ dependencies = [
  "proptest",
  "qrcodegen",
  "quick-xml",
- "r2d2",
- "r2d2_sqlite",
  "rand 0.8.5",
  "ratelimit",
  "regex",
@@ -1130,11 +1070,11 @@ dependencies = [
 
 [[package]]
 name = "deltachat-jsonrpc"
-version = "1.108.0"
+version = "1.109.0"
 dependencies = [
  "anyhow",
  "async-channel",
- "axum 0.6.4",
+ "axum",
  "deltachat",
  "env_logger 0.10.0",
  "futures",
@@ -1152,7 +1092,7 @@ dependencies = [
 
 [[package]]
 name = "deltachat-repl"
-version = "1.108.0"
+version = "1.109.0"
 dependencies = [
  "ansi_term",
  "anyhow",
@@ -1167,7 +1107,7 @@ dependencies = [
 
 [[package]]
 name = "deltachat-rpc-server"
-version = "1.108.0"
+version = "1.109.0"
 dependencies = [
  "anyhow",
  "deltachat-jsonrpc",
@@ -1190,7 +1130,7 @@ dependencies = [
 
 [[package]]
 name = "deltachat_ffi"
-version = "1.108.0"
+version = "1.109.0"
 dependencies = [
  "anyhow",
  "deltachat",
@@ -1924,15 +1864,6 @@ version = "1.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eabb4a44450da02c90444cf74558da904edde8fb4e9035a9a6a4e15445af0bd7"
 
-[[package]]
-name = "hashbrown"
-version = "0.11.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab5ef0d4909ef3724cc8cce6ccc8572c5c817592e9285f5464f8e86f8bd3726e"
-dependencies = [
- "ahash",
-]
-
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
@@ -1944,11 +1875,11 @@ dependencies = [
 
 [[package]]
 name = "hashlink"
-version = "0.7.0"
+version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7249a3129cbc1ffccd74857f81464a323a152173cdb134e0fd81bc803b29facf"
+checksum = "69fe1fcf8b4278d860ad0548329f892a3631fb63f82574df68275f34cdbe0ffa"
 dependencies = [
- "hashbrown 0.11.2",
+ "hashbrown",
 ]
 
 [[package]]
@@ -2190,7 +2121,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "10a35a97730320ffe8e2d410b5d3b69279b98d2c14bdb8b70ea89ecf7888d41e"
 dependencies = [
  "autocfg",
- "hashbrown 0.12.3",
+ "hashbrown",
 ]
 
 [[package]]
@@ -2349,9 +2280,9 @@ checksum = "292a948cd991e376cf75541fe5b97a1081d713c618b4f1b9500f8844e49eb565"
 
 [[package]]
 name = "libsqlite3-sys"
-version = "0.24.2"
+version = "0.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "898745e570c7d0453cc1fbc4a701eb6c662ed54e8fec8b7d14be137ebeeb9d14"
+checksum = "29f835d03d717946d28b1d1ed632eb6f0e24a299388ee623d0c23118d3e8a7fa"
 dependencies = [
  "cc",
  "openssl-sys",
@@ -2443,12 +2374,6 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73cbba799671b762df5a175adf59ce145165747bb891505c43d09aefbbf38beb"
 
-[[package]]
-name = "matchit"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b87248edafb776e59e6ee64a79086f65890d3510f2c656c000bf2a7e8a0aea40"
-
 [[package]]
 name = "md-5"
 version = "0.10.5"
@@ -3219,27 +3144,6 @@ version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20f14e071918cbeefc5edc986a7aa92c425dae244e003a35e1cdddb5ca39b5cb"
 
-[[package]]
-name = "r2d2"
-version = "0.8.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51de85fb3fb6524929c8a2eb85e6b6d363de4e8c48f9e2c2eac4944abc181c93"
-dependencies = [
- "log",
- "parking_lot",
- "scheduled-thread-pool",
-]
-
-[[package]]
-name = "r2d2_sqlite"
-version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6fdc8e4da70586127893be32b7adf21326a4c6b1aba907611edf467d13ffe895"
-dependencies = [
- "r2d2",
- "rusqlite",
-]
-
 [[package]]
 name = "radix_trie"
 version = "0.2.1"
@@ -3530,16 +3434,15 @@ dependencies = [
 
 [[package]]
 name = "rusqlite"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "85127183a999f7db96d1a976a309eebbfb6ea3b0b400ddd8340190129de6eb7a"
+checksum = "01e213bc3ecb39ac32e81e51ebe31fd888a940515173e3a18a35f8c6e896422a"
 dependencies = [
  "bitflags",
  "fallible-iterator",
  "fallible-streaming-iterator",
  "hashlink",
  "libsqlite3-sys",
- "memchr",
  "smallvec",
 ]
 
@@ -3700,15 +3603,6 @@ dependencies = [
  "windows-sys 0.36.1",
 ]
 
-[[package]]
-name = "scheduled-thread-pool"
-version = "0.2.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "977a7519bff143a44f842fd07e80ad1329295bd71686457f18e496736f4bf9bf"
-dependencies = [
- "parking_lot",
-]
-
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -3845,15 +3739,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "serde_path_to_error"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "184c643044780f7ceb59104cef98a5a6f12cb2288a7bc701ab93a362b49fd47d"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "serde_spanned"
 version = "0.6.1"
@@ -4366,19 +4251,7 @@ dependencies = [
  "futures-util",
  "log",
  "tokio",
- "tungstenite 0.17.3",
-]
-
-[[package]]
-name = "tokio-tungstenite"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54319c93411147bced34cb5609a80e0a8e44c5999c93903a81cd866630ec0bfd"
-dependencies = [
- "futures-util",
- "log",
- "tokio",
- "tungstenite 0.18.0",
+ "tungstenite",
 ]
 
 [[package]]
@@ -4628,25 +4501,6 @@ dependencies = [
  "utf-8",
 ]
 
-[[package]]
-name = "tungstenite"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30ee6ab729cd4cf0fd55218530c4522ed30b7b6081752839b68fcec8d0960788"
-dependencies = [
- "base64 0.13.1",
- "byteorder",
- "bytes",
- "http",
- "httparse",
- "log",
- "rand 0.8.5",
- "sha1",
- "thiserror",
- "url",
- "utf-8",
-]
-
 [[package]]
 name = "twofish"
 version = "0.7.1"
@@ -4704,7 +4558,7 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c5faade31a542b8b35855fff6e8def199853b2da8da256da52f52f1316ee3137"
 dependencies = [
- "hashbrown 0.12.3",
+ "hashbrown",
  "regex",
 ]
 
@@ -5166,7 +5020,7 @@ dependencies = [
  "async-channel",
  "async-mutex",
  "async-trait",
- "axum 0.5.17",
+ "axum",
  "futures",
  "futures-util",
  "log",
diff --git a/Cargo.toml b/Cargo.toml
index 62fc9b73a..26ebe0507 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "deltachat"
-version = "1.108.0"
+version = "1.109.0"
 edition = "2021"
 license = "MPL-2.0"
 rust-version = "1.63"
@@ -29,21 +29,24 @@ format-flowed = { path = "./format-flowed" }
 ratelimit = { path = "./deltachat-ratelimit" }
 
 anyhow = "1"
+async-channel = "1.8.0"
 async-imap = { git = "https://github.com/async-email/async-imap", branch = "master", default-features = false, features = ["runtime-tokio"] }
 async-native-tls = { version = "0.4", default-features = false, features = ["runtime-tokio"] }
 async-smtp = { version = "0.8", default-features = false, features = ["runtime-tokio"] }
-trust-dns-resolver = "0.22"
-tokio = { version = "1", features = ["fs", "rt-multi-thread", "macros"] }
-tokio-tar = { version = "0.3" } # TODO: integrate tokio into async-tar
+async_zip = { version = "0.0.9", default-features = false, features = ["deflate"] }
 backtrace = "0.3"
 base64 = "0.21"
 bitflags = "1.3"
 chrono = { version = "0.4", default-features=false, features = ["clock", "std"] }
+crossbeam-queue = "0.3"
 email = { git = "https://github.com/deltachat/rust-email", branch = "master" }
 encoded-words = { git = "https://github.com/async-email/encoded-words", branch = "master" }
 escaper = "0.1"
+fast-socks5 = "0.8"
 futures = "0.3"
+futures-lite = "1.12.0"
 hex = "0.4.0"
+humansize = "2"
 image = { version = "0.24.5", default-features=false, features = ["gif", "jpeg", "ico", "png", "pnm", "webp", "bmp"] }
 kamadak-exif = "0.5"
 lettre_email = { git = "https://github.com/deltachat/lettre", branch = "master" }
@@ -57,12 +60,12 @@ once_cell = "1.17.0"
 percent-encoding = "2.2"
 pgp = { version = "0.9", default-features = false }
 pretty_env_logger = { version = "0.4", optional = true }
+qrcodegen = "1.7.0"
 quick-xml = "0.27"
-r2d2 = "0.8"
-r2d2_sqlite = "0.20"
 rand = "0.8"
 regex = "1.7"
-rusqlite = { version = "0.27", features = ["sqlcipher"] }
+reqwest = { version = "0.11.14", features = ["json"] }
+rusqlite = { version = "0.28", features = ["sqlcipher"] }
 rust-hsluv = "0.1"
 sanitize-filename = "0.4"
 sendme = { git = "https://github.com/n0-computer/sendme", branch = "main", default-features = false }
@@ -73,21 +76,17 @@ sha2 = "0.10"
 smallvec = "1"
 strum = "0.24"
 strum_macros = "0.24"
-thiserror = "1"
-toml = "0.7"
-url = "2"
-uuid = { version = "1", features = ["serde", "v4"] }
-fast-socks5 = "0.8"
-humansize = "2"
-qrcodegen = "1.7.0"
 tagger = "4.3.4"
 textwrap = "0.16.0"
-async-channel = "1.8.0"
-futures-lite = "1.12.0"
-tokio-stream = { version = "0.1.11", features = ["fs"] }
+thiserror = "1"
 tokio-io-timeout = "1.2.0"
-reqwest = { version = "0.11.14", features = ["json"] }
-async_zip = { version = "0.0.9", default-features = false, features = ["deflate"] }
+tokio-stream = { version = "0.1.11", features = ["fs"] }
+tokio-tar = { version = "0.3" } # TODO: integrate tokio into async-tar
+tokio = { version = "1", features = ["fs", "rt-multi-thread", "macros"] }
+toml = "0.7"
+trust-dns-resolver = "0.22"
+url = "2"
+uuid = { version = "1", features = ["serde", "v4"] }
 
 [dev-dependencies]
 ansi_term = "0.12.0"
diff --git a/deltachat-ffi/Cargo.toml b/deltachat-ffi/Cargo.toml
index 1e0891cea..2bbec1c1f 100644
--- a/deltachat-ffi/Cargo.toml
+++ b/deltachat-ffi/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "deltachat_ffi"
-version = "1.108.0"
+version = "1.109.0"
 description = "Deltachat FFI"
 edition = "2018"
 readme = "README.md"
diff --git a/deltachat-ffi/deltachat.h b/deltachat-ffi/deltachat.h
index 980702a3e..1e9998488 100644
--- a/deltachat-ffi/deltachat.h
+++ b/deltachat-ffi/deltachat.h
@@ -4443,6 +4443,18 @@ void            dc_msg_set_text               (dc_msg_t* msg, const char* text);
 void            dc_msg_set_html               (dc_msg_t* msg, const char* html);
 
 
+/**
+ * Sets the email's subject. If it's empty, a default subject
+ * will be used (e.g. `Message from Alice` or `Re: <last subject>`).
+ * This does not alter any information in the database.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @param subject The new subject.
+ */
+void            dc_msg_set_subject            (dc_msg_t* msg, const char* subject);
+
+
 /**
  * Set different sender name for a message.
  * This overrides the name set by the dc_set_config()-option `displayname`.
diff --git a/deltachat-ffi/src/lib.rs b/deltachat-ffi/src/lib.rs
index 17104d238..a51d97367 100644
--- a/deltachat-ffi/src/lib.rs
+++ b/deltachat-ffi/src/lib.rs
@@ -2004,12 +2004,10 @@ pub unsafe extern "C" fn dc_create_contact(
     let ctx = &*context;
     let name = to_string_lossy(name);
 
-    block_on(async move {
-        Contact::create(ctx, &name, &to_string_lossy(addr))
-            .await
-            .map(|id| id.to_u32())
-            .unwrap_or(0)
-    })
+    block_on(Contact::create(ctx, &name, &to_string_lossy(addr)))
+        .log_err(ctx, "Cannot create contact")
+        .map(|id| id.to_u32())
+        .unwrap_or(0)
 }
 
 #[no_mangle]
@@ -3599,6 +3597,16 @@ pub unsafe extern "C" fn dc_msg_set_html(msg: *mut dc_msg_t, html: *const libc::
     ffi_msg.message.set_html(to_opt_string_lossy(html))
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_set_subject(msg: *mut dc_msg_t, subject: *const libc::c_char) {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_get_subject()");
+        return;
+    }
+    let ffi_msg = &mut *msg;
+    ffi_msg.message.set_subject(to_string_lossy(subject));
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn dc_msg_set_override_sender_name(
     msg: *mut dc_msg_t,
diff --git a/deltachat-jsonrpc/Cargo.toml b/deltachat-jsonrpc/Cargo.toml
index 0ca66a9e5..2ad9f2b83 100644
--- a/deltachat-jsonrpc/Cargo.toml
+++ b/deltachat-jsonrpc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "deltachat-jsonrpc"
-version = "1.108.0"
+version = "1.109.0"
 description = "DeltaChat JSON-RPC API"
 edition = "2021"
 default-run = "deltachat-jsonrpc-server"
@@ -28,7 +28,7 @@ sanitize-filename = "0.4"
 walkdir = "2.3.2"
 
 # optional dependencies
-axum = { version = "0.6.4", optional = true, features = ["ws"] }
+axum = { version = "0.5.9", optional = true, features = ["ws"] }
 env_logger = { version = "0.10.0", optional = true }
 
 [dev-dependencies]
diff --git a/deltachat-jsonrpc/typescript/package.json b/deltachat-jsonrpc/typescript/package.json
index e93c1f6b3..039057017 100644
--- a/deltachat-jsonrpc/typescript/package.json
+++ b/deltachat-jsonrpc/typescript/package.json
@@ -48,5 +48,5 @@
   },
   "type": "module",
   "types": "dist/deltachat.d.ts",
-  "version": "1.108.0"
+  "version": "1.109.0"
 }
diff --git a/deltachat-repl/Cargo.toml b/deltachat-repl/Cargo.toml
index 9dca2a2ae..59e3a3774 100644
--- a/deltachat-repl/Cargo.toml
+++ b/deltachat-repl/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "deltachat-repl"
-version = "1.108.0"
+version = "1.109.0"
 edition = "2021"
 
 [dependencies]
@@ -10,7 +10,7 @@ deltachat = { path = "..", features = ["internals"]}
 dirs = "4"
 log = "0.4.16"
 pretty_env_logger = "0.4"
-rusqlite = "0.27"
+rusqlite = "0.28"
 rustyline = "10"
 tokio = { version = "1", features = ["fs", "rt-multi-thread", "macros"] }
 
diff --git a/deltachat-rpc-server/Cargo.toml b/deltachat-rpc-server/Cargo.toml
index f678e2cb0..619841fc9 100644
--- a/deltachat-rpc-server/Cargo.toml
+++ b/deltachat-rpc-server/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "deltachat-rpc-server"
-version = "1.108.0"
+version = "1.109.0"
 description = "DeltaChat JSON-RPC server"
 edition = "2021"
 readme = "README.md"
diff --git a/package.json b/package.json
index e028cd28b..9045c36e2 100644
--- a/package.json
+++ b/package.json
@@ -60,5 +60,5 @@
     "test:mocha": "mocha -r esm node/test/test.js --growl --reporter=spec --bail --exit"
   },
   "types": "node/dist/index.d.ts",
-  "version": "1.108.0"
+  "version": "1.109.0"
 }
\ No newline at end of file
diff --git a/python/src/deltachat/account.py b/python/src/deltachat/account.py
index 61d74d793..e6749c7ba 100644
--- a/python/src/deltachat/account.py
+++ b/python/src/deltachat/account.py
@@ -6,7 +6,7 @@ from array import array
 from contextlib import contextmanager
 from email.utils import parseaddr
 from threading import Event
-from typing import Any, Dict, Generator, List, Optional, Union
+from typing import Any, Dict, Generator, List, Optional, Union, TYPE_CHECKING
 
 from . import const, hookspec
 from .capi import ffi, lib
@@ -22,6 +22,9 @@ from .cutil import (
 from .message import Message
 from .tracker import ConfigureTracker, ImexTracker
 
+if TYPE_CHECKING:
+    from .events import FFIEventTracker
+
 
 class MissingCredentials(ValueError):
     """Account is missing `addr` and `mail_pw` config values."""
@@ -60,6 +63,9 @@ class Account:
 
     MissingCredentials = MissingCredentials
 
+    _logid: str
+    _evtracker: "FFIEventTracker"
+
     def __init__(self, db_path, os_name=None, logging=True, closed=False) -> None:
         from .events import EventThread
 
diff --git a/python/src/deltachat/direct_imap.py b/python/src/deltachat/direct_imap.py
index 193924055..d95bd29ab 100644
--- a/python/src/deltachat/direct_imap.py
+++ b/python/src/deltachat/direct_imap.py
@@ -207,14 +207,14 @@ class IdleManager:
         return res
 
     def wait_for_new_message(self, timeout=None) -> bytes:
-        while 1:
+        while True:
             for item in self.check(timeout=timeout):
                 if b"EXISTS" in item or b"RECENT" in item:
                     return item
 
     def wait_for_seen(self, timeout=None) -> int:
         """Return first message with SEEN flag from a running idle-stream."""
-        while 1:
+        while True:
             for item in self.check(timeout=timeout):
                 if FETCH in item:
                     self.log(str(item))
diff --git a/python/src/deltachat/events.py b/python/src/deltachat/events.py
index d88876004..006095da0 100644
--- a/python/src/deltachat/events.py
+++ b/python/src/deltachat/events.py
@@ -108,7 +108,7 @@ class FFIEventTracker:
         return ev
 
     def iter_events(self, timeout=None, check_error=True):
-        while 1:
+        while True:
             yield self.get(timeout=timeout, check_error=check_error)
 
     def get_matching(self, event_name_regex, check_error=True, timeout=None):
@@ -119,14 +119,14 @@ class FFIEventTracker:
 
     def get_info_contains(self, regex: str) -> FFIEvent:
         rex = re.compile(regex)
-        while 1:
+        while True:
             ev = self.get_matching("DC_EVENT_INFO")
             if rex.search(ev.data2):
                 return ev
 
     def get_info_regex_groups(self, regex, check_error=True):
         rex = re.compile(regex)
-        while 1:
+        while True:
             ev = self.get_matching("DC_EVENT_INFO", check_error=check_error)
             m = rex.match(ev.data2)
             if m is not None:
@@ -137,7 +137,7 @@ class FFIEventTracker:
         This only works reliably if the connectivity doesn't change
         again too quickly, otherwise we might miss it.
         """
-        while 1:
+        while True:
             if self.account.get_connectivity() == connectivity:
                 return
             self.get_matching("DC_EVENT_CONNECTIVITY_CHANGED")
@@ -146,7 +146,7 @@ class FFIEventTracker:
         """Wait until the connectivity changes to `expected_next`.
         Fails the test if it changes to something else.
         """
-        while 1:
+        while True:
             current = self.account.get_connectivity()
             if current == expected_next:
                 return
@@ -156,7 +156,7 @@ class FFIEventTracker:
             self.get_matching("DC_EVENT_CONNECTIVITY_CHANGED")
 
     def wait_for_all_work_done(self):
-        while 1:
+        while True:
             if self.account.all_work_done():
                 return
             self.get_matching("DC_EVENT_CONNECTIVITY_CHANGED")
@@ -164,7 +164,7 @@ class FFIEventTracker:
     def ensure_event_not_queued(self, event_name_regex):
         __tracebackhide__ = True
         rex = re.compile(f"(?:{event_name_regex}).*")
-        while 1:
+        while True:
             try:
                 ev = self._event_queue.get(False)
             except Empty:
@@ -173,7 +173,7 @@ class FFIEventTracker:
                 assert not rex.match(ev.name), f"event found {ev}"
 
     def wait_securejoin_inviter_progress(self, target):
-        while 1:
+        while True:
             event = self.get_matching("DC_EVENT_SECUREJOIN_INVITER_PROGRESS")
             if event.data2 >= target:
                 print(f"** SECUREJOINT-INVITER PROGRESS {target}", self.account)
diff --git a/python/src/deltachat/testplugin.py b/python/src/deltachat/testplugin.py
index d9d3e4ebb..ebbb13aaf 100644
--- a/python/src/deltachat/testplugin.py
+++ b/python/src/deltachat/testplugin.py
@@ -275,6 +275,8 @@ class ACSetup:
     CONFIGURED = "CONFIGURED"
     IDLEREADY = "IDLEREADY"
 
+    _configured_events: Queue
+
     def __init__(self, testprocess, init_time):
         self._configured_events = Queue()
         self._account2state = {}
@@ -307,7 +309,7 @@ class ACSetup:
     def wait_one_configured(self, account):
         """wait until this account has successfully configured."""
         if self._account2state[account] == self.CONFIGURING:
-            while 1:
+            while True:
                 acc = self._pop_config_success()
                 if acc == account:
                     break
@@ -376,8 +378,13 @@ class ACSetup:
 
 
 class ACFactory:
+    """Account factory"""
+
+    init_time: float
     _finalizers: List[Callable[[], None]]
     _accounts: List[Account]
+    _acsetup: ACSetup
+    _preconfigured_keys: List[str]
 
     def __init__(self, request, testprocess, tmpdir, data) -> None:
         self.init_time = time.time()
@@ -429,14 +436,15 @@ class ACFactory:
         assert "addr" in configdict and "mail_pw" in configdict
         return configdict
 
-    def _get_cached_account(self, addr):
+    def _get_cached_account(self, addr) -> Optional[Account]:
         if addr in self.testprocess._addr2files:
             return self._getaccount(addr)
+        return None
 
-    def get_unconfigured_account(self, closed=False):
+    def get_unconfigured_account(self, closed=False) -> Account:
         return self._getaccount(closed=closed)
 
-    def _getaccount(self, try_cache_addr=None, closed=False):
+    def _getaccount(self, try_cache_addr=None, closed=False) -> Account:
         logid = f"ac{len(self._accounts) + 1}"
         # we need to use fixed database basename for maybe_cache_* functions to work
         path = self.tmpdir.mkdir(logid).join("dc.db")
@@ -450,10 +458,10 @@ class ACFactory:
         self._accounts.append(ac)
         return ac
 
-    def set_logging_default(self, logging):
+    def set_logging_default(self, logging) -> None:
         self._logging = bool(logging)
 
-    def remove_preconfigured_keys(self):
+    def remove_preconfigured_keys(self) -> None:
         self._preconfigured_keys = []
 
     def _preconfigure_key(self, account, addr):
@@ -491,7 +499,7 @@ class ACFactory:
         self._acsetup.init_logging(ac)
         return ac
 
-    def new_online_configuring_account(self, cloned_from=None, cache=False, **kwargs):
+    def new_online_configuring_account(self, cloned_from=None, cache=False, **kwargs) -> Account:
         if cloned_from is None:
             configdict = self.get_next_liveconfig()
         else:
@@ -513,7 +521,7 @@ class ACFactory:
         self._acsetup.start_configure(ac)
         return ac
 
-    def prepare_account_from_liveconfig(self, configdict):
+    def prepare_account_from_liveconfig(self, configdict) -> Account:
         ac = self.get_unconfigured_account()
         assert "addr" in configdict and "mail_pw" in configdict, configdict
         configdict.setdefault("bcc_self", False)
@@ -523,11 +531,11 @@ class ACFactory:
         self._preconfigure_key(ac, configdict["addr"])
         return ac
 
-    def wait_configured(self, account):
+    def wait_configured(self, account) -> None:
         """Wait until the specified account has successfully completed configure."""
         self._acsetup.wait_one_configured(account)
 
-    def bring_accounts_online(self):
+    def bring_accounts_online(self) -> None:
         print("bringing accounts online")
         self._acsetup.bring_online()
         print("all accounts online")
@@ -630,7 +638,7 @@ class BotProcess:
 
     def _run_stdout_thread(self) -> None:
         try:
-            while 1:
+            while True:
                 line = self.popen.stdout.readline()
                 if not line:
                     break
@@ -651,7 +659,7 @@ class BotProcess:
         for next_pattern in patterns:
             print("+++FNMATCH:", next_pattern)
             ignored = []
-            while 1:
+            while True:
                 line = self.stdout_queue.get()
                 if line is None:
                     if ignored:
diff --git a/python/src/deltachat/tracker.py b/python/src/deltachat/tracker.py
index 24665ea64..2dc2ad41b 100644
--- a/python/src/deltachat/tracker.py
+++ b/python/src/deltachat/tracker.py
@@ -85,7 +85,7 @@ class ConfigureTracker:
         self._imap_finished.wait()
 
     def wait_progress(self, data1=None):
-        while 1:
+        while True:
             evdata = self._progress.get()
             if data1 is None or evdata == data1:
                 break
diff --git a/python/tox.ini b/python/tox.ini
index 17905738f..6a50005c5 100644
--- a/python/tox.ini
+++ b/python/tox.ini
@@ -8,7 +8,7 @@ envlist =
 
 [testenv]
 commands = 
-    pytest -n6 --extra-info --reruns 2 --reruns-delay 5 -v -rsXx --ignored --strict-tls {posargs: tests examples}
+    pytest -n6 --extra-info -v -rsXx --ignored --strict-tls {posargs: tests examples}
     pip wheel . -w {toxworkdir}/wheelhouse --no-deps
 setenv =
 # Avoid stack overflow when Rust core is built without optimizations.
@@ -21,7 +21,6 @@ passenv =
     RUSTC_WRAPPER
 deps = 
     pytest
-    pytest-rerunfailures
     pytest-timeout
     pytest-xdist
     pdbpp
diff --git a/src/accounts.rs b/src/accounts.rs
index e01cc49c2..8ec3a34c8 100644
--- a/src/accounts.rs
+++ b/src/accounts.rs
@@ -1,7 +1,6 @@
 //! # Account manager module.
 
 use std::collections::BTreeMap;
-use std::future::Future;
 use std::path::{Path, PathBuf};
 
 use anyhow::{ensure, Context as _, Result};
@@ -151,7 +150,7 @@ impl Accounts {
         if let Some(cfg) = self.config.get_account(id) {
             let account_path = self.dir.join(cfg.dir);
 
-            try_many_times(|| fs::remove_dir_all(&account_path))
+            fs::remove_dir_all(&account_path)
                 .await
                 .context("failed to remove account data")?;
         }
@@ -187,10 +186,10 @@ impl Accounts {
             fs::create_dir_all(self.dir.join(&account_config.dir))
                 .await
                 .context("failed to create dir")?;
-            try_many_times(|| fs::rename(&dbfile, &new_dbfile))
+            fs::rename(&dbfile, &new_dbfile)
                 .await
                 .context("failed to rename dbfile")?;
-            try_many_times(|| fs::rename(&blobdir, &new_blobdir))
+            fs::rename(&blobdir, &new_blobdir)
                 .await
                 .context("failed to rename blobdir")?;
             if walfile.exists() {
@@ -215,7 +214,7 @@ impl Accounts {
             }
             Err(err) => {
                 let account_path = std::path::PathBuf::from(&account_config.dir);
-                try_many_times(|| fs::remove_dir_all(&account_path))
+                fs::remove_dir_all(&account_path)
                     .await
                     .context("failed to remove account data")?;
                 self.config.remove_account(account_config.id).await?;
@@ -472,33 +471,6 @@ impl Config {
     }
 }
 
-/// Spend up to 1 minute trying to do the operation.
-///
-/// Files may remain locked up to 30 seconds due to r2d2 bug:
-/// <https://github.com/sfackler/r2d2/issues/99>
-async fn try_many_times<F, Fut, T>(f: F) -> std::result::Result<(), T>
-where
-    F: Fn() -> Fut,
-    Fut: Future<Output = std::result::Result<(), T>>,
-{
-    let mut counter = 0;
-    loop {
-        counter += 1;
-
-        if let Err(err) = f().await {
-            if counter > 60 {
-                return Err(err);
-            }
-
-            // Wait 1 second and try again.
-            tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
-        } else {
-            break;
-        }
-    }
-    Ok(())
-}
-
 /// Configuration of a single account.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 struct AccountConfig {
diff --git a/src/chat.rs b/src/chat.rs
index cc217af15..dd88cdd30 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -3397,7 +3397,7 @@ pub async fn forward_msgs(context: &Context, msg_ids: &[MsgId], chat_id: ChatId)
             msg.param.remove(Param::WebxdcSummaryTimestamp);
             msg.in_reply_to = None;
 
-            // do not leak data as group names; a default subject is generated by mimfactory
+            // do not leak data as group names; a default subject is generated by mimefactory
             msg.subject = "".to_string();
 
             let new_msg_id: MsgId;
diff --git a/src/contact.rs b/src/contact.rs
index b86cbedb7..d27ccc361 100644
--- a/src/contact.rs
+++ b/src/contact.rs
@@ -13,6 +13,7 @@ use async_channel::{self as channel, Receiver, Sender};
 use deltachat_derive::{FromSql, ToSql};
 use once_cell::sync::Lazy;
 use regex::Regex;
+use rusqlite::OptionalExtension;
 use serde::{Deserialize, Serialize};
 use tokio::task;
 use tokio::time::{timeout, Duration};
@@ -520,8 +521,6 @@ impl Contact {
     /// Depending on the origin, both, "row_name" and "row_authname" are updated from "name".
     ///
     /// Returns the contact_id and a `Modifier` value indicating if a modification occurred.
-    ///
-    /// Returns None if the contact with such address cannot exist.
     pub(crate) async fn add_or_lookup(
         context: &Context,
         name: &str,
@@ -566,14 +565,12 @@ impl Contact {
         );
 
         let mut update_addr = false;
-        let mut row_id = 0;
 
-        if let Some((id, row_name, row_addr, row_origin, row_authname)) = context
-            .sql
-            .query_row_optional(
-                "SELECT id, name, addr, origin, authname \
-            FROM contacts WHERE addr=? COLLATE NOCASE;",
-                paramsv![addr.to_string()],
+        let row_id = context.sql.transaction(|transaction| {
+            let row = transaction.query_row(
+                "SELECT id, name, addr, origin, authname
+                 FROM contacts WHERE addr=? COLLATE NOCASE",
+                 [addr.to_string()],
                 |row| {
                     let row_id: isize = row.get(0)?;
                     let row_name: String = row.get(1)?;
@@ -582,120 +579,130 @@ impl Contact {
                     let row_authname: String = row.get(4)?;
 
                     Ok((row_id, row_name, row_addr, row_origin, row_authname))
-                },
-            )
-            .await?
-        {
-            let update_name = manual && name != row_name;
-            let update_authname = !manual
-                && name != row_authname
-                && !name.is_empty()
-                && (origin >= row_origin
-                    || origin == Origin::IncomingUnknownFrom
-                    || row_authname.is_empty());
+                }).optional()?;
 
-            row_id = u32::try_from(id)?;
-            if origin >= row_origin && addr.as_ref() != row_addr {
-                update_addr = true;
-            }
-            if update_name || update_authname || update_addr || origin > row_origin {
-                let new_name = if update_name {
-                    name.to_string()
-                } else {
-                    row_name
-                };
+            let row_id;
+            if let Some((id, row_name, row_addr, row_origin, row_authname)) = row {
+                let update_name = manual && name != row_name;
+                let update_authname = !manual
+                    && name != row_authname
+                    && !name.is_empty()
+                    && (origin >= row_origin
+                        || origin == Origin::IncomingUnknownFrom
+                        || row_authname.is_empty());
 
-                context
-                    .sql
-                    .execute(
-                        "UPDATE contacts SET name=?, addr=?, origin=?, authname=? WHERE id=?;",
-                        paramsv![
-                            new_name,
-                            if update_addr {
-                                addr.to_string()
-                            } else {
-                                row_addr
-                            },
-                            if origin > row_origin {
-                                origin
-                            } else {
-                                row_origin
-                            },
-                            if update_authname {
-                                name.to_string()
-                            } else {
-                                row_authname
-                            },
-                            row_id
-                        ],
-                    )
-                    .await
-                    .ok();
+                row_id = u32::try_from(id)?;
+                if origin >= row_origin && addr.as_ref() != row_addr {
+                    update_addr = true;
+                }
+                if update_name || update_authname || update_addr || origin > row_origin {
+                    let new_name = if update_name {
+                        name.to_string()
+                    } else {
+                        row_name
+                    };
 
-                if update_name || update_authname {
-                    // Update the contact name also if it is used as a group name.
-                    // This is one of the few duplicated data, however, getting the chat list is easier this way.
-                    let chat_id: Option<i32> = context.sql.query_get_value(
-                        "SELECT id FROM chats WHERE type=? AND id IN(SELECT chat_id FROM chats_contacts WHERE contact_id=?)",
-                        paramsv![Chattype::Single, isize::try_from(row_id)?]
-                    ).await?;
-                    if let Some(chat_id) = chat_id {
-                        let contact = Contact::get_by_id(context, ContactId::new(row_id)).await?;
-                        let chat_name = contact.get_display_name();
-                        match context
-                            .sql
-                            .execute(
-                                "UPDATE chats SET name=?1 WHERE id=?2 AND name!=?3",
-                                paramsv![chat_name, chat_id, chat_name],
-                            )
-                            .await
-                        {
-                            Err(err) => warn!(context, "Can't update chat name: {}", err),
-                            Ok(count) => {
-                                if count > 0 {
-                                    // Chat name updated
-                                    context.emit_event(EventType::ChatModified(ChatId::new(
-                                        chat_id.try_into()?,
-                                    )));
-                                }
+                    transaction
+                        .execute(
+                            "UPDATE contacts SET name=?, addr=?, origin=?, authname=? WHERE id=?;",
+                            paramsv![
+                                new_name,
+                                if update_addr {
+                                    addr.to_string()
+                                } else {
+                                    row_addr
+                                },
+                                if origin > row_origin {
+                                    origin
+                                } else {
+                                    row_origin
+                                },
+                                if update_authname {
+                                    name.to_string()
+                                } else {
+                                    row_authname
+                                },
+                                row_id
+                            ],
+                        )?;
+
+                    if update_name || update_authname {
+                        // Update the contact name also if it is used as a group name.
+                        // This is one of the few duplicated data, however, getting the chat list is easier this way.
+                        let chat_id: Option<ChatId> = transaction.query_row(
+                            "SELECT id FROM chats WHERE type=? AND id IN(SELECT chat_id FROM chats_contacts WHERE contact_id=?)",
+                            params![Chattype::Single, isize::try_from(row_id)?],
+                            |row| {
+                                let chat_id: ChatId = row.get(0)?;
+                                Ok(chat_id)
+                            }
+                        ).optional()?;
+
+                        if let Some(chat_id) = chat_id {
+                            let contact_id = ContactId::new(row_id);
+                            let (addr, name, authname) =
+                                transaction.query_row(
+                                    "SELECT addr, name, authname
+                                     FROM contacts
+                                     WHERE id=?",
+                                     params![contact_id],
+                                |row| {
+                                    let addr: String = row.get(0)?;
+                                    let name: String = row.get(1)?;
+                                    let authname: String = row.get(2)?;
+                                    Ok((addr, name, authname))
+                                })?;
+
+                            let chat_name = if !name.is_empty() {
+                                name
+                            } else if !authname.is_empty() {
+                                authname
+                            } else {
+                                addr
+                            };
+
+                            let count = transaction.execute(
+                                    "UPDATE chats SET name=?1 WHERE id=?2 AND name!=?1",
+                                    params![chat_name, chat_id])?;
+
+                            if count > 0 {
+                                // Chat name updated
+                                context.emit_event(EventType::ChatModified(chat_id));
                             }
                         }
                     }
+                    sth_modified = Modifier::Modified;
                 }
-                sth_modified = Modifier::Modified;
-            }
-        } else {
-            let update_name = manual;
-            let update_authname = !manual;
-
-            if let Ok(new_row_id) = context
-                .sql
-                .insert(
-                    "INSERT INTO contacts (name, addr, origin, authname) VALUES(?, ?, ?, ?);",
-                    paramsv![
-                        if update_name {
-                            name.to_string()
-                        } else {
-                            "".to_string()
-                        },
-                        addr,
-                        origin,
-                        if update_authname {
-                            name.to_string()
-                        } else {
-                            "".to_string()
-                        }
-                    ],
-                )
-                .await
-            {
-                row_id = u32::try_from(new_row_id)?;
-                sth_modified = Modifier::Created;
-                info!(context, "added contact id={} addr={}", row_id, &addr);
             } else {
-                error!(context, "Cannot add contact.");
+                let update_name = manual;
+                let update_authname = !manual;
+
+                transaction
+                    .execute(
+                        "INSERT INTO contacts (name, addr, origin, authname)
+                         VALUES (?, ?, ?, ?);",
+                        params![
+                            if update_name {
+                                name.to_string()
+                            } else {
+                                "".to_string()
+                            },
+                            addr,
+                            origin,
+                            if update_authname {
+                                name.to_string()
+                            } else {
+                                "".to_string()
+                            }
+                        ],
+                    )?;
+
+                sth_modified = Modifier::Created;
+                row_id = u32::try_from(transaction.last_insert_rowid())?;
+                info!(context, "added contact id={} addr={}", row_id, &addr);
             }
-        }
+            Ok(row_id)
+        }).await?;
 
         Ok((ContactId::new(row_id), sth_modified))
     }
diff --git a/src/imex.rs b/src/imex.rs
index df28fae63..24786d7e9 100644
--- a/src/imex.rs
+++ b/src/imex.rs
@@ -512,6 +512,9 @@ fn get_next_backup_path(folder: &Path, backup_time: i64) -> Result<(PathBuf, Pat
     bail!("could not create backup file, disk full?");
 }
 
+/// Exports the database to a separate file with the given passphrase.
+///
+/// Set passphrase to empty string to export the database unencrypted.
 async fn export_backup(context: &Context, dir: &Path, passphrase: String) -> Result<()> {
     // get a fine backup file name (the name includes the date so that multiple backup instances are possible)
     let now = time();
@@ -737,9 +740,9 @@ where
     Ok(())
 }
 
-/// Exports the database to *file*, encrypted using *passphrase*.
+/// Exports the database to *dest*, encrypted using *passphrase*.
 ///
-/// The directory of *file* must already exist, if *file* itself exists it will be
+/// The directory of *dest* must already exist, if *dest* itself exists it will be
 /// overwritten.
 ///
 /// This also verifies that IO is not running during the export.
@@ -750,20 +753,31 @@ async fn export_database(context: &Context, dest: &Path, passphrase: String) ->
     );
     let now = time().try_into().context("32-bit UNIX time overflow")?;
 
+    // TODO: Maybe introduce camino crate for UTF-8 paths where we need them.
+    let dest = dest
+        .to_str()
+        .with_context(|| format!("path {} is not valid unicode", dest.display()))?;
+
     context.sql.set_raw_config_int("backup_time", now).await?;
     sql::housekeeping(context).await.ok_or_log(context);
-    context
-        .sql
-        .execute("VACUUM;", paramsv![])
-        .await
-        .map_err(|e| warn!(context, "Vacuum failed, exporting anyway {}", e))
-        .ok();
-    context
-        .sql
-        .export(dest, passphrase)
-        .await
-        .with_context(|| format!("failed to backup database to {}", dest.display()))?;
-    Ok(())
+    let conn = context.sql.get_conn().await?;
+    tokio::task::block_in_place(move || {
+        conn.execute("VACUUM;", params![])
+            .map_err(|err| warn!(context, "Vacuum failed, exporting anyway {err}"))
+            .ok();
+        conn.execute(
+            "ATTACH DATABASE ? AS backup KEY ?",
+            paramsv![dest, passphrase],
+        )
+        .context("failed to attach backup database")?;
+        let res = conn
+            .query_row("SELECT sqlcipher_export('backup')", [], |_row| Ok(()))
+            .context("failed to export to attached backup database");
+        conn.execute("DETACH DATABASE backup", [])
+            .context("failed to detach backup database")?;
+        res?;
+        Ok(())
+    })
 }
 
 #[cfg(test)]
diff --git a/src/message.rs b/src/message.rs
index 44d6c1194..e4bae9a67 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -265,6 +265,8 @@ pub struct Message {
     pub(crate) text: Option<String>,
 
     /// Message subject.
+    ///
+    /// If empty, a default subject will be generated when sending.
     pub(crate) subject: String,
 
     /// `Message-ID` header value.
@@ -795,6 +797,12 @@ impl Message {
         self.text = text;
     }
 
+    /// Sets the email's subject. If it's empty, a default subject
+    /// will be used (e.g. `Message from Alice` or `Re: <last subject>`).
+    pub fn set_subject(&mut self, subject: String) {
+        self.subject = subject;
+    }
+
     /// Sets the file associated with a message.
     ///
     /// This function does not use the file or check if it exists,
diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index 2672c203d..43978c112 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -1612,6 +1612,22 @@ mod tests {
         assert_eq!(maybe_encode_words("äöü"), "=?utf-8?b?w6TDtsO8?=");
     }
 
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_manually_set_subject() -> Result<()> {
+        let t = TestContext::new_alice().await;
+        let chat = t.create_chat_with_contact("bob", "bob@example.org").await;
+
+        let mut msg = Message::new(Viewtype::Text);
+        msg.set_subject("Subjeeeeect".to_string());
+
+        let sent_msg = t.send_msg(chat.id, &mut msg).await;
+        let payload = sent_msg.payload();
+
+        assert_eq!(payload.match_indices("Subject: Subjeeeeect").count(), 1);
+
+        Ok(())
+    }
+
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_subject_from_mua() {
         // 1.: Receive a mail from an MUA
diff --git a/src/sql.rs b/src/sql.rs
index 6b967de17..4b4b190eb 100644
--- a/src/sql.rs
+++ b/src/sql.rs
@@ -4,10 +4,9 @@ use std::collections::{HashMap, HashSet};
 use std::convert::TryFrom;
 use std::path::Path;
 use std::path::PathBuf;
-use std::time::Duration;
 
 use anyhow::{bail, Context as _, Result};
-use rusqlite::{config::DbConfig, Connection, OpenFlags};
+use rusqlite::{self, config::DbConfig, Connection, OpenFlags, TransactionBehavior};
 use tokio::sync::RwLock;
 
 use crate::blob::BlobObject;
@@ -48,6 +47,9 @@ pub(crate) fn params_iter(iter: &[impl crate::ToSql]) -> impl Iterator<Item = &d
 }
 
 mod migrations;
+mod pool;
+
+use pool::{Pool, PooledConnection};
 
 /// A wrapper around the underlying Sqlite3 object.
 #[derive(Debug)]
@@ -56,7 +58,7 @@ pub struct Sql {
     pub(crate) dbfile: PathBuf,
 
     /// SQL connection pool.
-    pool: RwLock<Option<r2d2::Pool<r2d2_sqlite::SqliteConnectionManager>>>,
+    pool: RwLock<Option<Pool>>,
 
     /// None if the database is not open, true if it is open with passphrase and false if it is
     /// open without a passphrase.
@@ -122,31 +124,6 @@ impl Sql {
         // drop closes the connection
     }
 
-    /// Exports the database to a separate file with the given passphrase.
-    ///
-    /// Set passphrase to empty string to export the database unencrypted.
-    pub(crate) async fn export(&self, path: &Path, passphrase: String) -> Result<()> {
-        let path_str = path
-            .to_str()
-            .with_context(|| format!("path {path:?} is not valid unicode"))?;
-        let conn = self.get_conn().await?;
-        tokio::task::block_in_place(move || {
-            conn.execute(
-                "ATTACH DATABASE ? AS backup KEY ?",
-                paramsv![path_str, passphrase],
-            )
-            .context("failed to attach backup database")?;
-            let res = conn
-                .query_row("SELECT sqlcipher_export('backup')", [], |_row| Ok(()))
-                .context("failed to export to attached backup database");
-            conn.execute("DETACH DATABASE backup", [])
-                .context("failed to detach backup database")?;
-            res?;
-
-            Ok(())
-        })
-    }
-
     /// Imports the database from a separate file with the given passphrase.
     pub(crate) async fn import(&self, path: &Path, passphrase: String) -> Result<()> {
         let path_str = path
@@ -192,50 +169,15 @@ impl Sql {
         })
     }
 
-    fn new_pool(
-        dbfile: &Path,
-        passphrase: String,
-    ) -> Result<r2d2::Pool<r2d2_sqlite::SqliteConnectionManager>> {
-        let mut open_flags = OpenFlags::SQLITE_OPEN_NO_MUTEX;
-        open_flags.insert(OpenFlags::SQLITE_OPEN_READ_WRITE);
-        open_flags.insert(OpenFlags::SQLITE_OPEN_CREATE);
+    /// Creates a new connection pool.
+    fn new_pool(dbfile: &Path, passphrase: String) -> Result<Pool> {
+        let mut connections = Vec::new();
+        for _ in 0..3 {
+            let connection = new_connection(dbfile, &passphrase)?;
+            connections.push(connection);
+        }
 
-        // this actually creates min_idle database handles just now.
-        // therefore, with_init() must not try to modify the database as otherwise
-        // we easily get busy-errors (eg. table-creation, journal_mode etc. should be done on only one handle)
-        let mgr = r2d2_sqlite::SqliteConnectionManager::file(dbfile)
-            .with_flags(open_flags)
-            .with_init(move |c| {
-                c.execute_batch(&format!(
-                    "PRAGMA cipher_memory_security = OFF; -- Too slow on Android
-                     PRAGMA secure_delete=on;
-                     PRAGMA busy_timeout = {};
-                     PRAGMA temp_store=memory; -- Avoid SQLITE_IOERR_GETTEMPPATH errors on Android
-                     PRAGMA foreign_keys=on;
-                     ",
-                    Duration::from_secs(10).as_millis()
-                ))?;
-                c.pragma_update(None, "key", passphrase.clone())?;
-                // Try to enable auto_vacuum. This will only be
-                // applied if the database is new or after successful
-                // VACUUM, which usually happens before backup export.
-                // When auto_vacuum is INCREMENTAL, it is possible to
-                // use PRAGMA incremental_vacuum to return unused
-                // database pages to the filesystem.
-                c.pragma_update(None, "auto_vacuum", "INCREMENTAL".to_string())?;
-
-                c.pragma_update(None, "journal_mode", "WAL".to_string())?;
-                // Default synchronous=FULL is much slower. NORMAL is sufficient for WAL mode.
-                c.pragma_update(None, "synchronous", "NORMAL".to_string())?;
-                Ok(())
-            });
-
-        let pool = r2d2::Pool::builder()
-            .min_idle(Some(2))
-            .max_size(10)
-            .connection_timeout(Duration::from_secs(60))
-            .build(mgr)
-            .context("Can't build SQL connection pool")?;
+        let pool = Pool::new(connections);
         Ok(pool)
     }
 
@@ -393,12 +335,10 @@ impl Sql {
     }
 
     /// Allocates a connection from the connection pool and returns it.
-    pub async fn get_conn(
-        &self,
-    ) -> Result<r2d2::PooledConnection<r2d2_sqlite::SqliteConnectionManager>> {
+    pub(crate) async fn get_conn(&self) -> Result<PooledConnection> {
         let lock = self.pool.read().await;
         let pool = lock.as_ref().context("no SQL connection")?;
-        let conn = pool.get()?;
+        let conn = pool.get().await?;
 
         Ok(conn)
     }
@@ -437,6 +377,12 @@ impl Sql {
     ///
     /// If the function returns an error, the transaction will be rolled back. If it does not return an
     /// error, the transaction will be committed.
+    ///
+    /// Transactions started use IMMEDIATE behavior
+    /// rather than default DEFERRED behavior
+    /// to avoid "database is busy" errors
+    /// which may happen when DEFERRED transaction
+    /// is attempted to be promoted to a write transaction.
     pub async fn transaction<G, H>(&self, callback: G) -> Result<H>
     where
         H: Send + 'static,
@@ -444,7 +390,7 @@ impl Sql {
     {
         let mut conn = self.get_conn().await?;
         tokio::task::block_in_place(move || {
-            let mut transaction = conn.transaction()?;
+            let mut transaction = conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
             let ret = callback(&mut transaction);
 
             match ret {
@@ -642,6 +588,42 @@ impl Sql {
     }
 }
 
+/// Creates a new SQLite connection.
+///
+/// `path` is the database path.
+///
+/// `passphrase` is the SQLCipher database passphrase.
+/// Empty string if database is not encrypted.
+fn new_connection(path: &Path, passphrase: &str) -> Result<Connection> {
+    let mut flags = OpenFlags::SQLITE_OPEN_NO_MUTEX;
+    flags.insert(OpenFlags::SQLITE_OPEN_READ_WRITE);
+    flags.insert(OpenFlags::SQLITE_OPEN_CREATE);
+
+    let conn = Connection::open_with_flags(path, flags)?;
+    conn.execute_batch(
+        "PRAGMA cipher_memory_security = OFF; -- Too slow on Android
+         PRAGMA secure_delete=on;
+         PRAGMA busy_timeout = 60000; -- 60 seconds
+         PRAGMA temp_store=memory; -- Avoid SQLITE_IOERR_GETTEMPPATH errors on Android
+         PRAGMA foreign_keys=on;
+         ",
+    )?;
+    conn.pragma_update(None, "key", passphrase)?;
+    // Try to enable auto_vacuum. This will only be
+    // applied if the database is new or after successful
+    // VACUUM, which usually happens before backup export.
+    // When auto_vacuum is INCREMENTAL, it is possible to
+    // use PRAGMA incremental_vacuum to return unused
+    // database pages to the filesystem.
+    conn.pragma_update(None, "auto_vacuum", "INCREMENTAL".to_string())?;
+
+    conn.pragma_update(None, "journal_mode", "WAL".to_string())?;
+    // Default synchronous=FULL is much slower. NORMAL is sufficient for WAL mode.
+    conn.pragma_update(None, "synchronous", "NORMAL".to_string())?;
+
+    Ok(conn)
+}
+
 /// Cleanup the account to restore some storage and optimize the database.
 pub async fn housekeeping(context: &Context) -> Result<()> {
     if let Err(err) = remove_unused_files(context).await {
diff --git a/src/sql/pool.rs b/src/sql/pool.rs
new file mode 100644
index 000000000..fc7bf05bf
--- /dev/null
+++ b/src/sql/pool.rs
@@ -0,0 +1,102 @@
+//! Connection pool.
+
+use std::ops::{Deref, DerefMut};
+use std::sync::{Arc, Weak};
+
+use anyhow::{Context, Result};
+use crossbeam_queue::ArrayQueue;
+use rusqlite::Connection;
+use tokio::sync::{OwnedSemaphorePermit, Semaphore};
+
+/// Inner connection pool.
+#[derive(Debug)]
+struct InnerPool {
+    /// Available connections.
+    connections: ArrayQueue<Connection>,
+
+    /// Counts the number of available connections.
+    semaphore: Arc<Semaphore>,
+}
+
+impl InnerPool {
+    /// Puts a connection into the pool.
+    ///
+    /// The connection could be new or returned back.
+    fn put(&self, connection: Connection) {
+        self.connections.force_push(connection);
+    }
+}
+
+/// Pooled connection.
+pub struct PooledConnection {
+    /// Weak reference to the pool used to return the connection back.
+    pool: Weak<InnerPool>,
+
+    /// Only `None` right after moving the connection back to the pool.
+    conn: Option<Connection>,
+
+    /// Semaphore permit, dropped after returning the connection to the pool.
+    _permit: OwnedSemaphorePermit,
+}
+
+impl Drop for PooledConnection {
+    fn drop(&mut self) {
+        // Put the connection back unless the pool is already dropped.
+        if let Some(pool) = self.pool.upgrade() {
+            if let Some(conn) = self.conn.take() {
+                pool.put(conn);
+            }
+        }
+    }
+}
+
+impl Deref for PooledConnection {
+    type Target = Connection;
+
+    fn deref(&self) -> &Connection {
+        self.conn.as_ref().unwrap()
+    }
+}
+
+impl DerefMut for PooledConnection {
+    fn deref_mut(&mut self) -> &mut Connection {
+        self.conn.as_mut().unwrap()
+    }
+}
+
+/// Connection pool.
+#[derive(Clone, Debug)]
+pub struct Pool {
+    /// Reference to the actual connection pool.
+    inner: Arc<InnerPool>,
+}
+
+impl Pool {
+    /// Creates a new connection pool.
+    pub fn new(connections: Vec<Connection>) -> Self {
+        let inner = Arc::new(InnerPool {
+            connections: ArrayQueue::new(connections.len()),
+            semaphore: Arc::new(Semaphore::new(connections.len())),
+        });
+        for connection in connections {
+            inner.connections.force_push(connection);
+        }
+        Pool { inner }
+    }
+
+    /// Retrieves a connection from the pool.
+    pub async fn get(&self) -> Result<PooledConnection> {
+        let permit = self.inner.semaphore.clone().acquire_owned().await?;
+        let conn = self
+            .inner
+            .connections
+            .pop()
+            .context("got a permit when there are no connections in the pool")?;
+        let conn = PooledConnection {
+            pool: Arc::downgrade(&self.inner),
+            conn: Some(conn),
+            _permit: permit,
+        };
+        Ok(conn)
+    }
+}