diff --git a/.circleci/config.yml b/.circleci/config.yml
index 20fe3538a..3e3de12d5 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -138,6 +138,8 @@ jobs:
     steps:
       - *restore-workspace
       - *restore-cache
+      - run: rustup install $(cat rust-toolchain)
+      - run: rustup default $(cat rust-toolchain)
       - run:
           name: build docs, run tests and build wheels
           command: ci_scripts/run-python.sh
diff --git a/rust-toolchain b/rust-toolchain
index 202ebf953..22e904890 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2019-09-12
+nightly-2019-11-06
diff --git a/src/e2ee.rs b/src/e2ee.rs
index 805ad47be..7780d4dcd 100644
--- a/src/e2ee.rs
+++ b/src/e2ee.rs
@@ -498,7 +498,7 @@ fn decrypt_if_autocrypt_message(
     public_keyring_for_validate: &Keyring,
     ret_valid_signatures: &mut HashSet<String>,
     ret_gossip_headers: *mut *mut mailimf_fields,
-) -> Result<(bool)> {
+) -> Result<bool> {
     /* The returned bool is true if we detected an Autocrypt-encrypted
     message and successfully decrypted it. Decryption then modifies the
     passed in mime structure in place. The returned bool is false