move smtp-send chunking from chat.rs to smtp loop and use max-recipients value for the smtp transport in use, add chunking tests

`OutPreparing` is deprecated since 2024-12-07, replace it with `OutFailed`, such messages are
probably not interesting anymore. `OutMdnRcvd` is not used in the db for new messages since
a30c6ae1f7, `OutDelivered` is stored instead.

.github/workflows/ci.yml

@@ -41,6 +41,8 @@ jobs:
         shell: bash
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4
+        with:
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Run rustfmt
         run: cargo fmt --all -- --check
       - name: Run clippy
@@ -92,6 +94,8 @@ jobs:
           persist-credentials: false
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4
+        with:
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Rustdoc
         run: cargo doc --document-private-items --no-deps
 
@@ -135,6 +139,8 @@ jobs:
 
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4
+        with:
+          save-if: ${{ github.ref == 'refs/heads/main' }}
 
       - name: Install nextest
         uses: taiki-e/install-action@5f57d6cb7cd20b14a8a27f522884c4bc8a187458
@@ -169,6 +175,8 @@ jobs:
 
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4
+        with:
+          save-if: ${{ github.ref == 'refs/heads/main' }}
 
       - name: Build C library
         run: cargo build -p deltachat_ffi
@@ -195,6 +203,8 @@ jobs:
 
       - name: Cache rust cargo artifacts
         uses: swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4
+        with:
+          save-if: ${{ github.ref == 'refs/heads/main' }}
 
       - name: Build deltachat-rpc-server
         run: cargo build -p deltachat-rpc-server

Cargo.lock

@@ -934,9 +934,9 @@ checksum = "3d7b894f5411737b7867f4827955924d7c254fc9f4d91a6aad6b097804b1018b"
 
 [[package]]
 name = "colorutils-rs"
-version = "0.7.6"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e2fc25857fa523662de5cae84225b0e7bfb24a2a3f9ed8802fecf03df7252b1"
+checksum = "69abc9a8ed011e2b7946769f460b9e76e8b659ece9ef4001b9d8bba3489f796d"
 dependencies = [
  "erydanos",
  "half",
@@ -1301,9 +1301,9 @@ dependencies = [
 
 [[package]]
 name = "data-encoding"
-version = "2.10.0"
+version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7a1e2f27636f116493b8b860f5546edb47c8d8f8ea73e1d2a20be88e28d1fea"
+checksum = "a4ae5f15dda3c708c0ade84bfee31ccab44a3da4f88015ed22f63732abe300c8"
 
 [[package]]
 name = "dbl"
@@ -2662,7 +2662,7 @@ dependencies = [
  "hyper",
  "libc",
  "pin-project-lite",
- "socket2 0.5.9",
+ "socket2 0.6.3",
  "tokio",
  "tower-service",
  "tracing",
@@ -3268,9 +3268,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.184"
+version = "0.2.186"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "48f5d2a454e16a5ea0f4ced81bd44e4cfc7bd3a507b61887c99fd3538b28e4af"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
 
 [[package]]
 name = "libm"
@@ -3941,15 +3941,14 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 
 [[package]]
 name = "openssl"
-version = "0.10.78"
+version = "0.10.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f38c4372413cdaaf3cc79dd92d29d7d9f5ab09b51b10dded508fb90bb70b9222"
+checksum = "bf0b434746ee2832f4f0baf10137e1cabb18cbe6912c69e2e33263c45250f542"
 dependencies = [
  "bitflags 2.11.0",
  "cfg-if",
  "foreign-types",
  "libc",
- "once_cell",
  "openssl-macros",
  "openssl-sys",
 ]
@@ -3982,9 +3981,9 @@ dependencies = [
 
 [[package]]
 name = "openssl-sys"
-version = "0.9.114"
+version = "0.9.115"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13ce1245cd07fcc4cfdb438f7507b0c7e4f3849a69fd84d52374c66d83741bb6"
+checksum = "158fe5b292746440aa6e7a7e690e55aeb72d41505e2804c23c6973ad0e9c9781"
 dependencies = [
  "cc",
  "libc",

Cargo.toml

@@ -53,7 +53,7 @@ blake3 = "1.8.2"
 brotli = { version = "8", default-features=false, features = ["std"] }
 bytes = "1"
 chrono = { workspace = true, features = ["alloc", "clock", "std"] }
-colorutils-rs = { version = "0.7.5", default-features = false }
+colorutils-rs = { version = "0.8.0", default-features = false }
 data-encoding = "2.9.0"
 escaper = "0.1"
 fast-socks5 = "1"

deltachat-ffi/deltachat.h

@@ -4003,8 +4003,6 @@ int             dc_msg_get_viewtype           (const dc_msg_t* msg);
  *   Marked as read on IMAP and MDN may be sent. Use dc_markseen_msgs() to mark messages as being seen.
  *
  * Outgoing message states:
- * - @ref DC_STATE_OUT_PREPARING - For files which need time to be prepared before they can be sent,
- *   the message enters this state before @ref DC_STATE_OUT_PENDING. Deprecated.
  * - @ref DC_STATE_OUT_DRAFT - Message saved as draft using dc_set_draft()
  * - @ref DC_STATE_OUT_PENDING - The user has pressed the "send" button but the
  *   message is not yet sent and is pending in some way. Maybe we're offline (no checkmark).
@@ -5589,13 +5587,6 @@ int64_t         dc_lot_get_timestamp     (const dc_lot_t* lot);
  */
 #define         DC_STATE_IN_SEEN             16
 
-/**
- * Outgoing message being prepared. See dc_msg_get_state() for details.
- *
- * @deprecated 2024-12-07
- */
-#define         DC_STATE_OUT_PREPARING       18
-
 /**
  * Outgoing message drafted. See dc_msg_get_state() for details.
  */

deltachat-ffi/src/lot.rs

@@ -230,7 +230,6 @@ pub enum LotState {
     MsgInFresh = 10,
     MsgInNoticed = 13,
     MsgInSeen = 16,
-    MsgOutPreparing = 18,
     MsgOutDraft = 19,
     MsgOutPending = 20,
     MsgOutFailed = 24,
@@ -246,7 +245,6 @@ impl From<MessageState> for LotState {
             InFresh => LotState::MsgInFresh,
             InNoticed => LotState::MsgInNoticed,
             InSeen => LotState::MsgInSeen,
-            OutPreparing => LotState::MsgOutPreparing,
             OutDraft => LotState::MsgOutDraft,
             OutPending => LotState::MsgOutPending,
             OutFailed => LotState::MsgOutFailed,

deltachat-rpc-client/src/deltachat_rpc_client/const.py

@@ -190,7 +190,6 @@ class MessageState(IntEnum):
     IN_FRESH = 10
     IN_NOTICED = 13
     IN_SEEN = 16
-    OUT_PREPARING = 18
     OUT_DRAFT = 19
     OUT_PENDING = 20
     OUT_FAILED = 24

python/src/deltachat/chat.py

@@ -271,15 +271,6 @@ class Chat:
            sent out.  This is the same object as was passed in, which
            has been modified with the new state of the core.
         """
-        if msg.is_out_preparing():
-            assert msg.id != 0
-            # get a fresh copy of dc_msg, the core needs it
-            maybe_msg = Message.from_db(self.account, msg.id)
-            if maybe_msg is not None:
-                msg = maybe_msg
-            else:
-                raise ValueError("message does not exist")
-
         sent_id = lib.dc_send_msg(self.account._dc_context, self.id, msg._dc_msg)
         if sent_id == 0:
             raise ValueError("message could not be sent")
@@ -333,26 +324,6 @@ class Chat:
             raise ValueError("message could not be sent")
         return Message.from_db(self.account, sent_id)
 
-    def send_prepared(self, message):
-        """send a previously prepared message.
-
-        :param message: a :class:`Message` instance previously returned by
-                        :meth:`prepare_file`.
-        :raises ValueError: if message can not be sent.
-        :returns: a :class:`deltachat.message.Message` instance as sent out.
-        """
-        assert message.id != 0 and message.is_out_preparing()
-        # get a fresh copy of dc_msg, the core needs it
-        msg = Message.from_db(self.account, message.id)
-
-        # pass 0 as chat-id because core-docs say it's ok when out-preparing
-        sent_id = lib.dc_send_msg(self.account._dc_context, 0, msg._dc_msg)
-        if sent_id == 0:
-            raise ValueError("message could not be sent")
-        assert sent_id == msg.id
-        # modify message in place to avoid bad state for the caller
-        msg._dc_msg = Message.from_db(self.account, sent_id)._dc_msg
-
     def set_draft(self, message):
         """set message as draft.
 

python/src/deltachat/message.py

@@ -351,17 +351,12 @@ class Message:
     def is_outgoing(self):
         """Return True if Message is outgoing."""
         return lib.dc_msg_get_state(self._dc_msg) in (
-            const.DC_STATE_OUT_PREPARING,
             const.DC_STATE_OUT_PENDING,
             const.DC_STATE_OUT_FAILED,
             const.DC_STATE_OUT_MDN_RCVD,
             const.DC_STATE_OUT_DELIVERED,
         )
 
-    def is_out_preparing(self):
-        """Return True if Message is outgoing, but its file is being prepared."""
-        return self._msgstate == const.DC_STATE_OUT_PREPARING
-
     def is_out_pending(self):
         """Return True if Message is outgoing, but is pending (no single checkmark)."""
         return self._msgstate == const.DC_STATE_OUT_PENDING

src/chat.rs

@@ -2613,7 +2613,7 @@ pub async fn send_msg(context: &Context, chat_id: ChatId, msg: &mut Message) ->
         "chat_id cannot be a special chat: {chat_id}"
     );
 
-    if msg.state != MessageState::Undefined && msg.state != MessageState::OutPreparing {
+    if msg.state != MessageState::Undefined {
         msg.param.remove(Param::GuaranteeE2ee);
         msg.param.remove(Param::ForcePlaintext);
         // create_send_msg_jobs() will update `param` in the db.
@@ -2721,10 +2721,7 @@ async fn prepare_send_msg(
         None
     };
 
-    if matches!(
-        msg.state,
-        MessageState::Undefined | MessageState::OutPreparing
-    )
+    if msg.state == MessageState::Undefined
         // Legacy SecureJoin "v*-request" messages are unencrypted.
         && msg.param.get_cmd() != SystemMessage::SecurejoinMessage
         && chat.is_encrypted(context).await?
@@ -2937,8 +2934,8 @@ pub(crate) async fn create_send_msg_jobs(context: &Context, msg: &mut Message) -
 UPDATE msgs SET
     timestamp=(
         SELECT MAX(timestamp) FROM msgs INDEXED BY msgs_index7 WHERE
-            -- From `InFresh` to `OutMdnRcvd` inclusive except `OutDraft`.
-            state IN(10,13,16,18,20,24,26,28) AND
+            -- From `InFresh` to `OutDelivered` inclusive, except `OutDraft`.
+            state IN(10,13,16,18,20,24,26) AND
             hidden IN(0,1) AND
             chat_id=? AND
             id<=?
@@ -2957,7 +2954,6 @@ WHERE id=?
         )
         .await?;
 
-    let chunk_size = context.get_max_smtp_rcpt_to().await?;
     let trans_fn = |t: &mut rusqlite::Transaction| {
         let mut row_ids = Vec::<i64>::new();
 
@@ -2971,12 +2967,12 @@ WHERE id=?
             "INSERT INTO smtp (rfc724_mid, recipients, mime, msg_id)
             VALUES            (?1,         ?2,         ?3,   ?4)",
         )?;
-        for recipients_chunk in recipients.chunks(chunk_size) {
-            let recipients_chunk = recipients_chunk.join(" ");
+        if !recipients.is_empty() {
+            let all_recipients = recipients.join(" ");
             if let Some(pre_msg) = &rendered_pre_msg {
                 let row_id = stmt.execute((
                     &pre_msg.rfc724_mid,
-                    &recipients_chunk,
+                    &all_recipients,
                     &pre_msg.message,
                     msg.id,
                 ))?;
@@ -2984,7 +2980,7 @@ WHERE id=?
             }
             let row_id = stmt.execute((
                 &rendered_msg.rfc724_mid,
-                &recipients_chunk,
+                &all_recipients,
                 &rendered_msg.message,
                 msg.id,
             ))?;
@@ -4539,6 +4535,7 @@ pub async fn forward_msgs_2ctx(
 
         msg.state = MessageState::OutPending;
         msg.rfc724_mid = create_outgoing_rfc724_mid();
+        msg.pre_rfc724_mid.clear();
         msg.timestamp_sort = curr_timestamp;
         chat.prepare_msg_raw(ctx_dst, &mut msg, None).await?;
 

src/constants.rs

@@ -204,9 +204,6 @@ pub const MAX_RCVD_IMAGE_PIXELS: u32 = 50_000_000;
 // `max_smtp_rcpt_to` in the provider db.
 pub(crate) const DEFAULT_MAX_SMTP_RCPT_TO: usize = 50;
 
-/// Same as `DEFAULT_MAX_SMTP_RCPT_TO`, but for chatmail relays.
-pub(crate) const DEFAULT_CHATMAIL_MAX_SMTP_RCPT_TO: usize = 999;
-
 /// How far the last quota check needs to be in the past to be checked by the background function (in seconds).
 pub(crate) const DC_BACKGROUND_FETCH_QUOTA_CHECK_RATELIMIT: u64 = 12 * 60 * 60; // 12 hours
 

src/context.rs

@@ -16,7 +16,7 @@ use tokio::sync::{Mutex, Notify, RwLock};
 
 use crate::chat::{ChatId, get_chat_cnt};
 use crate::config::Config;
-use crate::constants::{self, DC_BACKGROUND_FETCH_QUOTA_CHECK_RATELIMIT, DC_VERSION_STR};
+use crate::constants::{DC_BACKGROUND_FETCH_QUOTA_CHECK_RATELIMIT, DC_VERSION_STR};
 use crate::contact::{Contact, ContactId};
 use crate::debug_logging::DebugLogging;
 use crate::events::{Event, EventEmitter, EventType, Events};
@@ -587,23 +587,6 @@ impl Context {
         self.get_config_bool(Config::IsChatmail).await
     }
 
-    /// Returns maximum number of recipients the provider allows to send a single email to.
-    pub(crate) async fn get_max_smtp_rcpt_to(&self) -> Result<usize> {
-        let is_chatmail = self.is_chatmail().await?;
-        let val = self
-            .get_configured_provider()
-            .await?
-            .and_then(|provider| provider.opt.max_smtp_rcpt_to)
-            .map_or_else(
-                || match is_chatmail {
-                    true => constants::DEFAULT_CHATMAIL_MAX_SMTP_RCPT_TO,
-                    false => constants::DEFAULT_MAX_SMTP_RCPT_TO,
-                },
-                usize::from,
-            );
-        Ok(val)
-    }
-
     /// Does a single round of fetching from IMAP and returns.
     ///
     /// Can be used even if I/O is currently stopped.

src/imap.rs

@@ -1503,7 +1503,7 @@ impl Session {
             .get_metadata(
                 mailbox,
                 options,
-                "(/shared/comment /shared/admin /shared/vendor/deltachat/irohrelay /shared/vendor/deltachat/turn)",
+                "(/shared/comment /shared/admin /shared/vendor/deltachat/irohrelay /shared/vendor/deltachat/turn /shared/vendor/deltachat/maxsmtprecipients)",
             )
             .await?;
         for m in metadata {
@@ -1539,6 +1539,21 @@ impl Session {
                         }
                     }
                 }
+                "/shared/vendor/deltachat/maxsmtprecipients" => {
+                    if let Some(value) = m.value.and_then(|v| v.parse::<u32>().ok()) {
+                        let transport_id = self.transport_id();
+                        context
+                            .sql
+                            .execute(
+                                "UPDATE transports \
+                                 SET max_smtp_rcpt_to=? WHERE id=?",
+                                (value, transport_id),
+                            )
+                            .await
+                            .log_err(context)
+                            .ok();
+                    }
+                }
                 _ => {}
             }
         }

src/message.rs

@@ -1381,13 +1381,8 @@ pub enum MessageState {
     /// IMAP and MDN may be sent.
     InSeen = 16,
 
-    /// For files which need time to be prepared before they can be
-    /// sent, the message enters this state before
-    /// OutPending.
-    ///
-    /// Deprecated 2024-12-07.
-    OutPreparing = 18,
-
+    // Deprecated 2024-12-07. Removed 2026-04.
+    // OutPreparing = 18,
     /// Message saved as draft.
     OutDraft = 19,
 
@@ -1420,7 +1415,6 @@ impl std::fmt::Display for MessageState {
                 Self::InFresh => "Fresh",
                 Self::InNoticed => "Noticed",
                 Self::InSeen => "Seen",
-                Self::OutPreparing => "Preparing",
                 Self::OutDraft => "Draft",
                 Self::OutPending => "Pending",
                 Self::OutFailed => "Failed",
@@ -1437,7 +1431,7 @@ impl MessageState {
         use MessageState::*;
         matches!(
             self,
-            OutPreparing | OutPending | OutDelivered | OutMdnRcvd // OutMdnRcvd can still fail because it could be a group message and only some recipients failed.
+            OutPending | OutDelivered | OutMdnRcvd // OutMdnRcvd can still fail because it could be a group message and only some recipients failed.
         )
     }
 
@@ -1446,7 +1440,7 @@ impl MessageState {
         use MessageState::*;
         matches!(
             self,
-            OutPreparing | OutDraft | OutPending | OutFailed | OutDelivered | OutMdnRcvd
+            OutDraft | OutPending | OutFailed | OutDelivered | OutMdnRcvd
         )
     }
 

src/net/dns.rs

@@ -231,10 +231,7 @@ static DNS_PRELOAD: LazyLock<HashMap<&'static str, Vec<IpAddr>>> = LazyLock::new
     HashMap::from([
         (
             "imap.163.com",
-            vec![
-                IpAddr::V4(Ipv4Addr::new(111, 124, 203, 45)),
-                IpAddr::V4(Ipv4Addr::new(111, 124, 203, 50)),
-            ],
+            vec![IpAddr::V4(Ipv4Addr::new(111, 124, 203, 45))],
         ),
         (
             "smtp.163.com",
@@ -425,12 +422,12 @@ static DNS_PRELOAD: LazyLock<HashMap<&'static str, Vec<IpAddr>>> = LazyLock::new
             "nine.testrun.org",
             vec![
                 IpAddr::V4(Ipv4Addr::new(128, 140, 126, 197)),
+                IpAddr::V4(Ipv4Addr::new(116, 202, 233, 236)),
                 IpAddr::V4(Ipv4Addr::new(216, 144, 228, 100)),
-                IpAddr::V4(Ipv4Addr::new(77, 42, 49, 41)),
+                IpAddr::V6(Ipv6Addr::new(0x2a01, 0x4f8, 0x241, 0x4ce8, 0, 0, 0, 2)),
                 IpAddr::V6(Ipv6Addr::new(
                     0x2001, 0x41d0, 0x701, 0x1100, 0, 0, 0, 0x8ab1,
                 )),
-                IpAddr::V6(Ipv6Addr::new(0x2a01, 0x4f9, 0xfff1, 0x59, 0, 0, 0, 1)),
             ],
         ),
         (
@@ -700,10 +697,6 @@ static DNS_PRELOAD: LazyLock<HashMap<&'static str, Vec<IpAddr>>> = LazyLock::new
             "chatmail.hackea.org",
             vec![IpAddr::V4(Ipv4Addr::new(82, 165, 11, 85))],
         ),
-        (
-            "chat.adminforge.de",
-            vec![IpAddr::V4(Ipv4Addr::new(94, 130, 17, 142))],
-        ),
         (
             "chika.aangat.lahat.computer",
             vec![IpAddr::V4(Ipv4Addr::new(71, 19, 150, 113))],
@@ -745,46 +738,6 @@ static DNS_PRELOAD: LazyLock<HashMap<&'static str, Vec<IpAddr>>> = LazyLock::new
             "danneskjold.de",
             vec![IpAddr::V4(Ipv4Addr::new(46, 62, 216, 132))],
         ),
-        (
-            "chat.in-the.eu",
-            vec![IpAddr::V4(Ipv4Addr::new(78, 46, 190, 129))],
-        ),
-        (
-            "chat.nuvon.app",
-            vec![IpAddr::V4(Ipv4Addr::new(178, 238, 38, 165))],
-        ),
-        (
-            "nibblehole.com",
-            vec![IpAddr::V4(Ipv4Addr::new(94, 247, 42, 209))],
-        ),
-        (
-            "chat.zashm.org",
-            vec![IpAddr::V4(Ipv4Addr::new(91, 245, 76, 39))],
-        ),
-        (
-            "chat.sus.fr",
-            vec![IpAddr::V4(Ipv4Addr::new(152, 67, 76, 190))],
-        ),
-        (
-            "delta.thelab.uno",
-            vec![IpAddr::V4(Ipv4Addr::new(146, 59, 228, 39))],
-        ),
-        (
-            "chat.vim.wtf",
-            vec![IpAddr::V4(Ipv4Addr::new(116, 203, 206, 170))],
-        ),
-        (
-            "uninterest.ing",
-            vec![IpAddr::V4(Ipv4Addr::new(172, 245, 70, 237))],
-        ),
-        (
-            "sweetfern.net",
-            vec![IpAddr::V4(Ipv4Addr::new(178, 156, 228, 133))],
-        ),
-        (
-            "delta.disobey.net",
-            vec![IpAddr::V4(Ipv4Addr::new(37, 74, 102, 44))],
-        ),
         (
             "darkrun.dev",
             vec![IpAddr::V4(Ipv4Addr::new(72, 11, 149, 146))],

src/quota.rs

@@ -66,12 +66,6 @@ impl Context {
 
     /// Updates `quota.recent`, sets `quota.modified` to the current time
     /// and emits an event to let the UIs update connectivity view.
-    ///
-    /// Moreover, once each time quota gets larger than `QUOTA_WARN_THRESHOLD_PERCENTAGE`,
-    /// a device message is added.
-    /// As the message is added only once, the user is not spammed
-    /// in case for some providers the quota is always at ~100%
-    /// and new space is allocated as needed.
     pub(crate) async fn update_recent_quota(
         &self,
         session: &mut ImapSession,

src/receive_imf.rs

@@ -806,8 +806,6 @@ UPDATE config SET value=? WHERE keyname='configured_addr' AND value!=?1
                 if transport_changed {
                     info!(context, "Primary transport changed to {from_addr:?}.");
                     context.sql.uncache_raw_config("configured_addr").await;
-
-                    // Regenerate User ID in V4 keys.
                     context.self_public_key.lock().await.take();
 
                     context.emit_event(EventType::TransportsModified);

src/smtp.rs

@@ -2,6 +2,8 @@
 
 mod connect;
 pub mod send;
+#[cfg(test)]
+mod chunking_tests;
 
 use anyhow::{Context as _, Error, Result, bail, format_err};
 use async_smtp::response::{Category, Code, Detail};
@@ -10,6 +12,7 @@ use tokio::task;
 
 use crate::chat::{ChatId, add_info_msg_with_cmd};
 use crate::config::Config;
+use crate::constants;
 use crate::contact::{Contact, ContactId};
 use crate::context::Context;
 use crate::events::EventType;
@@ -34,6 +37,9 @@ pub(crate) struct Smtp {
     /// Email address we are sending from.
     from: Option<EmailAddress>,
 
+    /// Transport used for the current connection.
+    transport_id: Option<u32>,
+
     /// Timestamp of last successful send/receive network interaction
     /// (eg connect or send succeeded). On initialization and disconnect
     /// it is set to None.
@@ -60,6 +66,7 @@ impl Smtp {
             task::spawn(async move { transport.quit().await });
         }
         self.last_success = None;
+        self.transport_id = None;
     }
 
     /// Return true if smtp was connected but is not known to
@@ -89,9 +96,10 @@ impl Smtp {
         }
 
         self.connectivity.set_connecting(context);
-        let (_transport_id, lp) = ConfiguredLoginParam::load(context)
+        let (transport_id, lp) = ConfiguredLoginParam::load(context)
             .await?
             .context("Not configured")?;
+        self.transport_id = Some(transport_id);
         let proxy_config = ProxyConfig::load(context).await?;
         self.connect(
             context,
@@ -165,6 +173,7 @@ impl Smtp {
     }
 }
 
+#[derive(Debug)]
 pub(crate) enum SendResult {
     /// Message was sent successfully.
     Success,
@@ -176,13 +185,36 @@ pub(crate) enum SendResult {
     Retry,
 }
 
+pub(crate) trait SmtpSender: Send {
+    fn send_chunk<'a>(
+        &'a mut self,
+        context: &'a Context,
+        recipients: &'a [async_smtp::EmailAddress],
+        body: &'a str,
+    ) -> futures::future::BoxFuture<'a, SendResult>;
+}
+
+struct RealSmtpSender<'a> {
+    smtp: &'a mut Smtp,
+}
+
+impl SmtpSender for RealSmtpSender<'_> {
+    fn send_chunk<'a>(
+        &'a mut self,
+        context: &'a Context,
+        recipients: &'a [async_smtp::EmailAddress],
+        body: &'a str,
+    ) -> futures::future::BoxFuture<'a, SendResult> {
+        Box::pin(smtp_send(context, recipients, body, self.smtp))
+    }
+}
+
 /// Tries to send a message.
 pub(crate) async fn smtp_send(
     context: &Context,
     recipients: &[async_smtp::EmailAddress],
     message: &str,
     smtp: &mut Smtp,
-    msg_id: Option<MsgId>,
 ) -> SendResult {
     if recipients.is_empty() {
         return SendResult::Success;
@@ -310,25 +342,6 @@ pub(crate) async fn smtp_send(
         Ok(()) => SendResult::Success,
     };
 
-    if let SendResult::Failure(err) = &status
-        && let Some(msg_id) = msg_id
-    {
-        // We couldn't send the message, so mark it as failed
-        match Message::load_from_db(context, msg_id).await {
-            Ok(mut msg) => {
-                if let Err(err) = message::set_msg_failed(context, &mut msg, &err.to_string()).await
-                {
-                    error!(context, "Failed to mark {msg_id} as failed: {err:#}.");
-                }
-            }
-            Err(err) => {
-                error!(
-                    context,
-                    "Failed to load {msg_id} to mark it as failed: {err:#}."
-                );
-            }
-        }
-    }
     status
 }
 
@@ -406,7 +419,40 @@ pub(crate) async fn send_msg_to_smtp(
         )
         .collect::<Vec<_>>();
 
-    let status = smtp_send(context, &recipients_list, body.as_str(), smtp, Some(msg_id)).await;
+    let transport_id = smtp
+        .transport_id
+        .context("SMTP not connected to a transport")?;
+    let chunk_size = max_smtp_rcpt_to(context, transport_id).await?;
+
+    let mut sender = RealSmtpSender { smtp };
+    let (status, start_idx) = send_smtp_chunks(
+        context,
+        &recipients_list,
+        body.as_str(),
+        chunk_size,
+        &mut sender,
+    )
+    .await;
+
+    let unsent_saved = start_idx < recipients_list.len();
+    if let Some(unsent) = recipients_list.get(start_idx..)
+        && !unsent.is_empty()
+    {
+        let unsent_str: String = unsent
+            .iter()
+            .map(|a| a.as_ref())
+            .collect::<Vec<&str>>()
+            .join(" ");
+        context
+            .sql
+            .execute(
+                "UPDATE smtp SET recipients=? WHERE id=?",
+                (unsent_str, rowid),
+            )
+            .await
+            .log_err(context)
+            .ok();
+    }
 
     match status {
         SendResult::Retry => {}
@@ -455,10 +501,15 @@ pub(crate) async fn send_msg_to_smtp(
                     .await?;
                 };
             }
-            context
-                .sql
-                .execute("DELETE FROM smtp WHERE id=?", (rowid,))
-                .await?;
+            if let Some(mut msg) = Message::load_from_db_optional(context, msg_id).await? {
+                message::set_msg_failed(context, &mut msg, &err.to_string()).await?;
+            }
+            if !unsent_saved {
+                context
+                    .sql
+                    .execute("DELETE FROM smtp WHERE id=?", (rowid,))
+                    .await?;
+            }
         }
     };
 
@@ -470,10 +521,39 @@ pub(crate) async fn send_msg_to_smtp(
             }
             Ok(())
         }
-        SendResult::Failure(err) => Err(format_err!("{err}")),
+        SendResult::Failure(err) => {
+            if unsent_saved {
+                Err(format_err!("Retry"))
+            } else {
+                Err(format_err!("{err}"))
+            }
+        }
     }
 }
 
+async fn max_smtp_rcpt_to(context: &Context, transport_id: u32) -> Result<usize> {
+    let limit = context
+        .sql
+        .query_row_optional(
+            "SELECT max_smtp_rcpt_to FROM transports WHERE id=?",
+            (transport_id,),
+            |row| row.get::<_, u32>(0),
+        )
+        .await?
+        .unwrap_or(0);
+
+    if limit > 0 {
+        return Ok(limit as usize);
+    }
+
+    let val = context
+        .get_configured_provider()
+        .await?
+        .and_then(|provider| provider.opt.max_smtp_rcpt_to)
+        .map_or(constants::DEFAULT_MAX_SMTP_RCPT_TO, usize::from);
+    Ok(val)
+}
+
 pub(crate) async fn msg_has_pending_smtp_job(
     context: &Context,
     msg_id: MsgId,
@@ -600,7 +680,7 @@ async fn send_mdn_rfc724_mid(
         })
         .collect();
 
-    match smtp_send(context, &recipients, &body, smtp, None).await {
+    match smtp_send(context, &recipients, &body, smtp).await {
         SendResult::Success => {
             if !recipients.is_empty() {
                 info!(context, "Successfully sent MDN for {rfc724_mid}.");
@@ -722,3 +802,22 @@ pub(crate) async fn add_self_recipients(
     }
     Ok(())
 }
+
+#[allow(clippy::arithmetic_side_effects)]
+pub(crate) async fn send_smtp_chunks(
+    context: &Context,
+    recipients: &[async_smtp::EmailAddress],
+    body: &str,
+    chunk_size: usize,
+    sender: &mut (dyn SmtpSender + Send),
+) -> (SendResult, usize) {
+    for (i, chunk) in recipients.chunks(chunk_size).enumerate() {
+        let status = sender.send_chunk(context, chunk, body).await;
+        match status {
+            SendResult::Success => continue,
+            SendResult::Failure(_) => return (status, (i + 1) * chunk_size),
+            SendResult::Retry => return (status, i * chunk_size),
+        }
+    }
+    (SendResult::Success, recipients.len())
+}

src/smtp/chunking_tests.rs

@@ -0,0 +1,102 @@
+use crate::smtp::{send_smtp_chunks, SendResult, SmtpSender};
+use crate::test_utils::TestContextManager;
+use crate::context::Context;
+use anyhow::Result;
+use futures::future::{BoxFuture, FutureExt};
+
+/// Result the mock should return on the designated call.
+enum MockFailure {
+    Transient,
+    Permanent,
+}
+
+struct MockSmtpSender {
+    call_count: usize,
+    fail_on_call: Option<(usize, MockFailure)>,
+}
+
+impl SmtpSender for MockSmtpSender {
+    fn send_chunk<'a>(
+        &'a mut self,
+        _context: &'a Context,
+        _recipients: &'a [async_smtp::EmailAddress],
+        _body: &'a str,
+    ) -> BoxFuture<'a, SendResult> {
+        self.call_count += 1;
+        let count = self.call_count;
+        let fail_on = self.fail_on_call.as_ref().map(|(n, _)| *n);
+        let is_permanent = matches!(
+            self.fail_on_call,
+            Some((_, MockFailure::Permanent))
+        );
+        async move {
+            if fail_on == Some(count) {
+                if is_permanent {
+                    return SendResult::Failure(
+                        anyhow::format_err!("permanent error"),
+                    );
+                }
+                return SendResult::Retry;
+            }
+            SendResult::Success
+        }
+        .boxed()
+    }
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_send_smtp_chunks() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = tcm.alice().await;
+
+    let recipients: Vec<_> = ["r1@ex.org", "r2@ex.org", "r3@ex.org", "r4@ex.org", "r5@ex.org"]
+        .iter()
+        .map(|a| async_smtp::EmailAddress::new(a.to_string()).unwrap())
+        .collect();
+
+    // All chunks succeed.
+    let mut sender = MockSmtpSender { call_count: 0, fail_on_call: None };
+    let (status, processed) =
+        send_smtp_chunks(&alice.ctx, &recipients, "body", 2, &mut sender).await;
+    assert!(matches!(status, SendResult::Success));
+    assert_eq!(processed, 5);
+    assert_eq!(sender.call_count, 3); // chunks: [2, 2, 1]
+
+    // Second chunk gets a transient error, only first chunk's recipients are processed.
+    let mut sender =
+        MockSmtpSender { call_count: 0, fail_on_call: Some((2, MockFailure::Transient)) };
+    let (status, processed) =
+        send_smtp_chunks(&alice.ctx, &recipients, "body", 2, &mut sender).await;
+    assert!(matches!(status, SendResult::Retry));
+    assert_eq!(processed, 2);
+    assert_eq!(sender.call_count, 2);
+
+    // Last chunk gets a transient error, first two chunks' recipients are processed.
+    let mut sender =
+        MockSmtpSender { call_count: 0, fail_on_call: Some((3, MockFailure::Transient)) };
+    let (status, processed) =
+        send_smtp_chunks(&alice.ctx, &recipients, "body", 2, &mut sender).await;
+    assert!(matches!(status, SendResult::Retry));
+    assert_eq!(processed, 4);
+    assert_eq!(sender.call_count, 3);
+
+    // Second chunk gets a permanent error; processed includes the failed chunk.
+    let mut sender =
+        MockSmtpSender { call_count: 0, fail_on_call: Some((2, MockFailure::Permanent)) };
+    let (status, processed) =
+        send_smtp_chunks(&alice.ctx, &recipients, "body", 2, &mut sender).await;
+    assert!(matches!(status, SendResult::Failure(_)));
+    assert_eq!(processed, 4);
+    assert_eq!(sender.call_count, 2);
+
+    // Last chunk gets a permanent error; processed includes the failed chunk.
+    let mut sender =
+        MockSmtpSender { call_count: 0, fail_on_call: Some((3, MockFailure::Permanent)) };
+    let (status, processed) =
+        send_smtp_chunks(&alice.ctx, &recipients, "body", 2, &mut sender).await;
+    assert!(matches!(status, SendResult::Failure(_)));
+    assert_eq!(processed, 6); // capped at (i+1)*chunk_size, may exceed len
+    assert_eq!(sender.call_count, 3);
+
+    Ok(())
+}

src/sql/migrations.rs

@@ -2373,6 +2373,27 @@ ALTER TABLE contacts ADD COLUMN name_normalized TEXT;
         .await?;
     }
 
+    inc_and_check(&mut migration_version, 152)?;
+    if dbversion < migration_version {
+        sql.execute_migration(
+            "
+UPDATE msgs SET state=26 WHERE state=28; -- Change OutMdnRcvd to OutDelivered.
+UPDATE msgs SET state=19 WHERE state=24; -- Change OutPreparing to OutFailed.
+            ",
+            migration_version,
+        )
+        .await?;
+    }
+
+    inc_and_check(&mut migration_version, 153)?;
+    if dbversion < migration_version {
+        sql.execute_migration(
+            "ALTER TABLE transports ADD COLUMN max_smtp_rcpt_to INTEGER NOT NULL DEFAULT 0",
+            migration_version,
+        )
+        .await?;
+    }
+
     let new_version = sql
         .get_raw_config_int(VERSION_CFG)
         .await?

src/tests/pre_messages/forward_and_save.rs

@@ -1,4 +1,6 @@
 //! Tests about forwarding and saving Pre-Messages
+use std::time::Duration;
+
 use anyhow::Result;
 use pretty_assertions::assert_eq;
 
@@ -8,6 +10,7 @@ use crate::chatlist::get_last_message_for_chat;
 use crate::download::{DownloadState, PRE_MSG_ATTACHMENT_SIZE_THRESHOLD};
 use crate::message::{Message, Viewtype};
 use crate::test_utils::TestContextManager;
+use crate::tests::pre_messages::util::send_large_file_message;
 
 /// Test that forwarding Pre-Message should forward additional text to not be empty
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
@@ -86,6 +89,43 @@ async fn test_forwarding_pre_message_empty_text() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_receive_both() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+    let alice_chat_id = alice.create_group_with_members("", &[bob]).await;
+
+    let (pre_message, post_message, alice_msg_id) =
+        send_large_file_message(alice, alice_chat_id, Viewtype::File, &vec![0u8; 200_000]).await?;
+
+    let msg = bob.recv_msg(&pre_message).await;
+    let _ = bob.recv_msg_trash(&post_message).await;
+    let msg = Message::load_from_db(bob, msg.id).await?;
+    assert_eq!(msg.download_state(), DownloadState::Done);
+    assert_eq!(msg.text, "test".to_owned());
+
+    forward_msgs(alice, &[alice_msg_id], alice_chat_id).await?;
+    let rev_order = false;
+    let msg = bob
+        .recv_msg(
+            &alice
+                .pop_sent_msg_ex(rev_order, Duration::ZERO)
+                .await
+                .unwrap(),
+        )
+        .await;
+    assert_eq!(msg.download_state(), DownloadState::Available);
+    assert_eq!(msg.is_forwarded(), true);
+    assert_eq!(msg.text, "test".to_owned());
+    let _ = bob.recv_msg_trash(&alice.pop_sent_msg().await).await;
+    let msg = Message::load_from_db(bob, msg.id).await?;
+    assert_eq!(msg.download_state(), DownloadState::Done);
+    assert_eq!(msg.is_forwarded(), true);
+    assert_eq!(msg.text, "test".to_owned());
+    Ok(())
+}
+
 /// Test that forwarding Pre-Message should forward additional text to not be empty
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_saving_pre_message_empty_text() -> Result<()> {

src/transport.rs

@@ -791,7 +791,18 @@ pub(crate) async fn sync_transports(
     context
         .sql
         .transaction(|transaction| {
+            let configured_addr = transaction.query_row(
+                "SELECT value FROM config WHERE keyname='configured_addr'",
+                (),
+                |row| {
+                    let addr: String = row.get(0)?;
+                    Ok(addr)
+                },
+            )?;
             for RemovedTransportData { addr, timestamp } in removed_transports {
+                if *addr == configured_addr {
+                    continue;
+                }
                 modified |= transaction.execute(
                     "DELETE FROM transports
                      WHERE addr=? AND add_timestamp<=?",

src/webxdc.rs

@@ -550,7 +550,7 @@ impl Context {
 
         let send_now = !matches!(
             instance.state,
-            MessageState::Undefined | MessageState::OutPreparing | MessageState::OutDraft
+            MessageState::Undefined | MessageState::OutDraft
         );
 
         status_update.uid = Some(create_id());