feat: Remove imap::Session::sync_seen_flags() (#7742)

This way they also can be processed by `markseen_msgs()` resulting in MDNs which improves
multi-device synchronization and updates contacts' `last_seen`. I.e. leave it up to the UIs.

deltachat-ffi/deltachat.h

@@ -6755,6 +6755,7 @@ void dc_event_unref(dc_event_t* event);
  * UI usually only takes action in case call UI was opened before, otherwise the event should be ignored.
  *
  * @param data1 (int) msg_id ID of the message referring to the call
+ * @param data2 (int) 1 if the call was accepted from this device (process).
  */
  #define DC_EVENT_INCOMING_CALL_ACCEPTED                  2560
 

deltachat-ffi/src/lib.rs

@@ -680,7 +680,6 @@ pub unsafe extern "C" fn dc_event_get_data2_int(event: *mut dc_event_t) -> libc:
         | EventType::ChatModified(_)
         | EventType::ChatDeleted { .. }
         | EventType::WebxdcRealtimeAdvertisementReceived { .. }
-        | EventType::IncomingCallAccepted { .. }
         | EventType::OutgoingCallAccepted { .. }
         | EventType::CallEnded { .. }
         | EventType::EventChannelOverflow { .. }
@@ -703,6 +702,9 @@ pub unsafe extern "C" fn dc_event_get_data2_int(event: *mut dc_event_t) -> libc:
         } => status_update_serial.to_u32() as libc::c_int,
         EventType::WebxdcRealtimeData { data, .. } => data.len() as libc::c_int,
         EventType::IncomingCall { has_video, .. } => *has_video as libc::c_int,
+        EventType::IncomingCallAccepted {
+            from_this_device, ..
+        } => *from_this_device as libc::c_int,
 
         #[allow(unreachable_patterns)]
         #[cfg(test)]

deltachat-jsonrpc/src/api/types/events.rs

@@ -441,6 +441,8 @@ pub enum EventType {
         msg_id: u32,
         /// ID of the chat which the message belongs to.
         chat_id: u32,
+        /// The call was accepted from this device (process).
+        from_this_device: bool,
     },
 
     /// Outgoing call accepted.
@@ -634,9 +636,14 @@ impl From<CoreEventType> for EventType {
                 place_call_info,
                 has_video,
             },
-            CoreEventType::IncomingCallAccepted { msg_id, chat_id } => IncomingCallAccepted {
+            CoreEventType::IncomingCallAccepted {
+                msg_id,
+                chat_id,
+                from_this_device,
+            } => IncomingCallAccepted {
                 msg_id: msg_id.to_u32(),
                 chat_id: chat_id.to_u32(),
+                from_this_device,
             },
             CoreEventType::OutgoingCallAccepted {
                 msg_id,

deltachat-rpc-client/tests/test_something.py

@@ -439,6 +439,35 @@ def test_reaction_seen_on_another_dev(acfactory) -> None:
     assert chat_id == alice2_chat_bob.id
 
 
+def test_2nd_device_events_when_msgs_are_seen(acfactory) -> None:
+    alice, bob = acfactory.get_online_accounts(2)
+    alice2 = alice.clone()
+    alice2.start_io()
+
+    # Get an accepted chat, otherwise alice2 won't be notified about the 2nd message.
+    chat_alice2 = alice2.create_chat(bob)
+    chat_id_alice2 = chat_alice2.get_basic_snapshot().id
+
+    chat_bob_alice = bob.create_chat(alice)
+    chat_bob_alice.send_text("Hello!")
+    msg_alice = alice.wait_for_incoming_msg()
+    assert alice2.wait_for_incoming_msg_event().chat_id == chat_id_alice2
+    chat_bob_alice.send_text("What's new?")
+    assert alice2.wait_for_incoming_msg_event().chat_id == chat_id_alice2
+    chat_alice2 = alice2.get_chat_by_id(chat_id_alice2)
+    assert chat_alice2.get_fresh_message_count() == 2
+
+    msg_alice.mark_seen()
+    assert alice2.wait_for_msgs_changed_event().chat_id == chat_id_alice2
+    assert chat_alice2.get_fresh_message_count() == 1
+
+    msg_id = alice.wait_for_msgs_changed_event().msg_id
+    msg = alice.get_message_by_id(msg_id)
+    msg.mark_seen()
+    assert alice2.wait_for_event(EventType.MSGS_NOTICED).chat_id == chat_id_alice2
+    assert chat_alice2.get_fresh_message_count() == 0
+
+
 def test_is_bot(acfactory) -> None:
     """Test that we can recognize messages submitted by bots."""
     alice, bob = acfactory.get_online_accounts(2)

src/accounts.rs

@@ -686,13 +686,27 @@ impl Config {
         file.write_all(toml::to_string_pretty(&self.inner)?.as_bytes())
             .await
             .context("failed to write a tmp config")?;
-        file.sync_data()
+
+        // We use `sync_all()` and not `sync_data()` here.
+        // This translates to `fsync()` instead of `fdatasync()`.
+        // `fdatasync()` may be insufficient for newely created files
+        // and may not even synchronize the file size on some operating systems,
+        // resulting in a truncated file.
+        file.sync_all()
             .await
             .context("failed to sync a tmp config")?;
         drop(file);
         fs::rename(&tmp_path, &self.file)
             .await
             .context("failed to rename config")?;
+        // Sync the rename().
+        #[cfg(not(windows))]
+        {
+            let parent = self.file.parent().context("No parent directory")?;
+            let parent_file = fs::File::open(parent).await?;
+            parent_file.sync_all().await?;
+        }
+
         Ok(())
     }
 

src/calls.rs

@@ -11,7 +11,7 @@ use crate::context::{Context, WeakContext};
 use crate::events::EventType;
 use crate::headerdef::HeaderDef;
 use crate::log::warn;
-use crate::message::{Message, MsgId, Viewtype};
+use crate::message::{Message, MsgId, Viewtype, markseen_msgs};
 use crate::mimeparser::{MimeMessage, SystemMessage};
 use crate::net::dns::lookup_host_with_cache;
 use crate::param::Param;
@@ -249,6 +249,7 @@ impl Context {
         if chat.is_contact_request() {
             chat.id.accept(self).await?;
         }
+        markseen_msgs(self, vec![call_id]).await?;
 
         // send an acceptance message around: to the caller as well as to the other devices of the callee
         let mut msg = Message {
@@ -265,6 +266,7 @@ impl Context {
         self.emit_event(EventType::IncomingCallAccepted {
             msg_id: call.msg.id,
             chat_id: call.msg.chat_id,
+            from_this_device: true,
         });
         self.emit_msgs_changed(call.msg.chat_id, call_id);
         Ok(())
@@ -283,6 +285,7 @@ impl Context {
         if !call.is_accepted() {
             if call.is_incoming() {
                 call.mark_as_ended(self).await?;
+                markseen_msgs(self, vec![call_id]).await?;
                 let declined_call_str = stock_str::declined_call(self).await;
                 call.update_text(self, &declined_call_str).await?;
             } else {
@@ -430,6 +433,7 @@ impl Context {
                         self.emit_event(EventType::IncomingCallAccepted {
                             msg_id: call.msg.id,
                             chat_id: call.msg.chat_id,
+                            from_this_device: false,
                         });
                     } else {
                         let accept_call_info = mime_message

src/calls/calls_tests.rs

@@ -2,6 +2,7 @@ use super::*;
 use crate::chat::forward_msgs;
 use crate::config::Config;
 use crate::constants::DC_CHAT_ID_TRASH;
+use crate::message::MessageState;
 use crate::receive_imf::receive_imf;
 use crate::test_utils::{TestContext, TestContextManager};
 
@@ -115,9 +116,28 @@ async fn accept_call() -> Result<CallSetup> {
     // Bob accepts the incoming call
     bob.accept_incoming_call(bob_call.id, ACCEPT_INFO.to_string())
         .await?;
+    assert_eq!(bob_call.id.get_state(&bob).await?, MessageState::InSeen);
+    // Bob sends an MDN to Alice.
+    assert_eq!(
+        bob.sql
+            .count(
+                "SELECT COUNT(*) FROM smtp_mdns WHERE msg_id=? AND from_id=?",
+                (bob_call.id, bob_call.from_id)
+            )
+            .await?,
+        1
+    );
     assert_text(&bob, bob_call.id, "Incoming video call").await?;
     bob.evtracker
-        .get_matching(|evt| matches!(evt, EventType::IncomingCallAccepted { .. }))
+        .get_matching(|evt| {
+            matches!(
+                evt,
+                EventType::IncomingCallAccepted {
+                    from_this_device: true,
+                    ..
+                }
+            )
+        })
         .await;
     let sent2 = bob.pop_sent_msg().await;
     let info = bob
@@ -131,7 +151,15 @@ async fn accept_call() -> Result<CallSetup> {
     bob2.recv_msg_trash(&sent2).await;
     assert_text(&bob, bob_call.id, "Incoming video call").await?;
     bob2.evtracker
-        .get_matching(|evt| matches!(evt, EventType::IncomingCallAccepted { .. }))
+        .get_matching(|evt| {
+            matches!(
+                evt,
+                EventType::IncomingCallAccepted {
+                    from_this_device: false,
+                    ..
+                }
+            )
+        })
         .await;
     let info = bob2
         .load_call_by_id(bob2_call.id)
@@ -200,9 +228,20 @@ async fn test_accept_call_callee_ends() -> Result<()> {
         bob2_call,
         ..
     } = accept_call().await?;
+    assert_eq!(bob_call.id.get_state(&bob).await?, MessageState::InSeen);
 
     // Bob has accepted the call and also ends it
     bob.end_call(bob_call.id).await?;
+    // Bob sends an MDN to Alice.
+    assert_eq!(
+        bob.sql
+            .count(
+                "SELECT COUNT(*) FROM smtp_mdns WHERE msg_id=? AND from_id=?",
+                (bob_call.id, bob_call.from_id)
+            )
+            .await?,
+        1
+    );
     assert_text(&bob, bob_call.id, "Incoming video call\n<1 minute").await?;
     bob.evtracker
         .get_matching(|evt| matches!(evt, EventType::CallEnded { .. }))
@@ -328,8 +367,18 @@ async fn test_callee_rejects_call() -> Result<()> {
     } = setup_call().await?;
 
     // Bob has accepted Alice before, but does not want to talk with Alice
-    bob_call.chat_id.accept(&bob).await?;
     bob.end_call(bob_call.id).await?;
+    assert_eq!(bob_call.id.get_state(&bob).await?, MessageState::InSeen);
+    // Bob sends an MDN to Alice.
+    assert_eq!(
+        bob.sql
+            .count(
+                "SELECT COUNT(*) FROM smtp_mdns WHERE msg_id=? AND from_id=?",
+                (bob_call.id, bob_call.from_id)
+            )
+            .await?,
+        1
+    );
     assert_text(&bob, bob_call.id, "Declined call").await?;
     bob.evtracker
         .get_matching(|evt| matches!(evt, EventType::CallEnded { .. }))
@@ -370,6 +419,35 @@ async fn test_callee_rejects_call() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_callee_sees_contact_request_call() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+
+    let alice_chat = alice.create_chat(bob).await;
+    alice
+        .place_outgoing_call(alice_chat.id, PLACE_INFO.to_string(), true)
+        .await?;
+    let sent1 = alice.pop_sent_msg().await;
+    let bob_call = bob.recv_msg(&sent1).await;
+    // Bob can't end_call() because the contact request isn't accepted, but he can mark the call as
+    // seen.
+    markseen_msgs(bob, vec![bob_call.id]).await?;
+    assert_eq!(bob_call.id.get_state(bob).await?, MessageState::InSeen);
+    // Bob sends an MDN only to self so that an unaccepted contact can't know anything.
+    assert_eq!(
+        bob.sql
+            .count(
+                "SELECT COUNT(*) FROM smtp_mdns WHERE msg_id=? AND from_id=?",
+                (bob_call.id, ContactId::SELF)
+            )
+            .await?,
+        1
+    );
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_caller_cancels_call() -> Result<()> {
     // Alice calls Bob

src/chat/chat_tests.rs

@@ -746,7 +746,7 @@ async fn test_leave_group() -> Result<()> {
 
     assert_eq!(get_chat_contacts(&alice, alice_chat_id).await?.len(), 1);
 
-    assert_eq!(rcvd_leave_msg.state, MessageState::InSeen);
+    assert_eq!(rcvd_leave_msg.state, MessageState::InNoticed);
 
     alice.emit_event(EventType::Test);
     alice
@@ -4733,9 +4733,10 @@ async fn test_sync_broadcast_and_send_message() -> Result<()> {
         vec![a2b_contact_id]
     );
 
-    // alice2's smeared clock may be behind alice's one, so "hi" from alice2 may appear before "You
-    // joined the channel." for bob.
-    SystemTime::shift(Duration::from_secs(1));
+    // alice2's smeared clock may be behind alice1's one, so we need to work around "hi" appearing
+    // before "You joined the channel." for bob. alice1 makes 3 more calls of
+    // create_smeared_timestamp() than alice2 does as of 2026-03-10.
+    SystemTime::shift(Duration::from_secs(3));
     tcm.section("Alice's second device sends a message to the channel");
     let sent_msg = alice2.send_text(a2_broadcast_id, "hi").await;
     let msg = bob.recv_msg(&sent_msg).await;

src/events/payload.rs

@@ -397,6 +397,8 @@ pub enum EventType {
         msg_id: MsgId,
         /// ID of the chat which the message belongs to.
         chat_id: ChatId,
+        /// The call was accepted from this device (process).
+        from_this_device: bool,
     },
 
     /// Outgoing call accepted.

src/imap.rs

@@ -6,7 +6,7 @@
 use std::{
     cmp::max,
     cmp::min,
-    collections::{BTreeMap, BTreeSet, HashMap},
+    collections::{BTreeMap, HashMap},
     iter::Peekable,
     mem::take,
     sync::atomic::Ordering,
@@ -24,8 +24,7 @@ use url::Url;
 use crate::calls::{
     UnresolvedIceServer, create_fallback_ice_servers, create_ice_servers_from_metadata,
 };
-use crate::chat::{self, ChatId, ChatIdBlocked, add_device_msg};
-use crate::chatlist_events;
+use crate::chat::{self, ChatIdBlocked, add_device_msg};
 use crate::config::Config;
 use crate::constants::{self, Blocked, DC_VERSION_STR};
 use crate::contact::ContactId;
@@ -33,7 +32,7 @@ use crate::context::Context;
 use crate::events::EventType;
 use crate::headerdef::{HeaderDef, HeaderDefMap};
 use crate::log::{LogExt, warn};
-use crate::message::{self, Message, MessageState, MessengerMessage, MsgId};
+use crate::message::{self, Message, MessengerMessage};
 use crate::mimeparser;
 use crate::net::proxy::ProxyConfig;
 use crate::net::session::SessionStream;
@@ -1147,113 +1146,6 @@ impl Session {
         Ok(())
     }
 
-    /// Synchronizes `\Seen` flags using `CONDSTORE` extension.
-    pub(crate) async fn sync_seen_flags(&mut self, context: &Context, folder: &str) -> Result<()> {
-        if !self.can_condstore() {
-            info!(
-                context,
-                "Server does not support CONDSTORE, skipping flag synchronization."
-            );
-            return Ok(());
-        }
-
-        if context.get_config_bool(Config::TeamProfile).await? {
-            return Ok(());
-        }
-
-        let folder_exists = self
-            .select_with_uidvalidity(context, folder)
-            .await
-            .context("Failed to select folder")?;
-        if !folder_exists {
-            return Ok(());
-        }
-
-        let mailbox = self
-            .selected_mailbox
-            .as_ref()
-            .with_context(|| format!("No mailbox selected, folder: {folder}"))?;
-
-        // Check if the mailbox supports MODSEQ.
-        // We are not interested in actual value of HIGHESTMODSEQ.
-        if mailbox.highest_modseq.is_none() {
-            info!(
-                context,
-                "Mailbox {} does not support mod-sequences, skipping flag synchronization.", folder
-            );
-            return Ok(());
-        }
-
-        let transport_id = self.transport_id();
-        let mut updated_chat_ids = BTreeSet::new();
-        let uid_validity = get_uidvalidity(context, transport_id, folder)
-            .await
-            .with_context(|| format!("failed to get UID validity for folder {folder}"))?;
-        let mut highest_modseq = get_modseq(context, transport_id, folder)
-            .await
-            .with_context(|| format!("failed to get MODSEQ for folder {folder}"))?;
-        let mut list = self
-            .uid_fetch("1:*", format!("(FLAGS) (CHANGEDSINCE {highest_modseq})"))
-            .await
-            .context("failed to fetch flags")?;
-
-        let mut got_unsolicited_fetch = false;
-
-        while let Some(fetch) = list
-            .try_next()
-            .await
-            .context("failed to get FETCH result")?
-        {
-            let uid = if let Some(uid) = fetch.uid {
-                uid
-            } else {
-                info!(context, "FETCH result contains no UID, skipping");
-                got_unsolicited_fetch = true;
-                continue;
-            };
-            let is_seen = fetch.flags().any(|flag| flag == Flag::Seen);
-            if is_seen
-                && let Some(chat_id) = mark_seen_by_uid(context, transport_id, folder, uid_validity, uid)
-                    .await
-                    .with_context(|| {
-                        format!("Transport {transport_id}: Failed to update seen status for msg {folder}/{uid}")
-                    })?
-            {
-                updated_chat_ids.insert(chat_id);
-            }
-
-            if let Some(modseq) = fetch.modseq {
-                if modseq > highest_modseq {
-                    highest_modseq = modseq;
-                }
-            } else {
-                warn!(context, "FETCH result contains no MODSEQ");
-            }
-        }
-        drop(list);
-
-        if got_unsolicited_fetch {
-            // We got unsolicited FETCH, which means some flags
-            // have been modified while our request was in progress.
-            // We may or may not have these new flags as a part of the response,
-            // so better skip next IDLE and do another round of flag synchronization.
-            self.new_mail = true;
-        }
-
-        set_modseq(context, transport_id, folder, highest_modseq)
-            .await
-            .with_context(|| format!("failed to set MODSEQ for folder {folder}"))?;
-        if !updated_chat_ids.is_empty() {
-            context.on_archived_chats_maybe_noticed();
-        }
-        for updated_chat_id in updated_chat_ids {
-            context.emit_event(EventType::MsgsNoticed(updated_chat_id));
-            chatlist_events::emit_chatlist_item_changed(context, updated_chat_id);
-        }
-
-        Ok(())
-    }
-
     /// Fetches a list of messages by server UID.
     ///
     /// Sends pairs of UID and info about each downloaded message to the provided channel.
@@ -2152,71 +2044,6 @@ pub(crate) async fn prefetch_should_download(
     Ok(should_download)
 }
 
-/// Marks messages in `msgs` table as seen, searching for them by UID.
-///
-/// Returns updated chat ID if any message was marked as seen.
-async fn mark_seen_by_uid(
-    context: &Context,
-    transport_id: u32,
-    folder: &str,
-    uid_validity: u32,
-    uid: u32,
-) -> Result<Option<ChatId>> {
-    if let Some((msg_id, chat_id)) = context
-        .sql
-        .query_row_optional(
-            "SELECT id, chat_id FROM msgs
-                 WHERE id > 9 AND rfc724_mid IN (
-                   SELECT rfc724_mid FROM imap
-                   WHERE transport_id=?
-                   AND folder=?
-                   AND uidvalidity=?
-                   AND uid=?
-                   LIMIT 1
-                 )",
-            (transport_id, &folder, uid_validity, uid),
-            |row| {
-                let msg_id: MsgId = row.get(0)?;
-                let chat_id: ChatId = row.get(1)?;
-                Ok((msg_id, chat_id))
-            },
-        )
-        .await
-        .with_context(|| format!("failed to get msg and chat ID for IMAP message {folder}/{uid}"))?
-    {
-        let updated = context
-            .sql
-            .execute(
-                "UPDATE msgs SET state=?1
-                     WHERE (state=?2 OR state=?3)
-                     AND id=?4",
-                (
-                    MessageState::InSeen,
-                    MessageState::InFresh,
-                    MessageState::InNoticed,
-                    msg_id,
-                ),
-            )
-            .await
-            .with_context(|| format!("failed to update msg {msg_id} state"))?
-            > 0;
-
-        if updated {
-            msg_id
-                .start_ephemeral_timer(context)
-                .await
-                .with_context(|| format!("failed to start ephemeral timer for message {msg_id}"))?;
-            Ok(Some(chat_id))
-        } else {
-            // Message state has not changed.
-            Ok(None)
-        }
-    } else {
-        // There is no message is `msgs` table matching the given UID.
-        Ok(None)
-    }
-}
-
 /// Schedule marking the message as Seen on IMAP by adding all known IMAP messages corresponding to
 /// the given Message-ID to `imap_markseen` table.
 pub(crate) async fn markseen_on_imap_table(context: &Context, message_id: &str) -> Result<()> {
@@ -2314,17 +2141,6 @@ pub(crate) async fn set_modseq(
     Ok(())
 }
 
-async fn get_modseq(context: &Context, transport_id: u32, folder: &str) -> Result<u64> {
-    Ok(context
-        .sql
-        .query_get_value(
-            "SELECT modseq FROM imap_sync WHERE transport_id=? AND folder=?",
-            (transport_id, folder),
-        )
-        .await?
-        .unwrap_or(0))
-}
-
 /// Whether to ignore fetching messages from a folder.
 ///
 /// This caters for the [`Config::OnlyFetchMvbox`] setting which means mails from folders

src/imap/imap_tests.rs

@@ -1,4 +1,5 @@
 use super::*;
+use crate::chat::ChatId;
 use crate::contact::Contact;
 use crate::test_utils::TestContext;
 

src/message.rs

@@ -1934,6 +1934,7 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
             // We also don't send read receipts for contact requests.
             // Read receipts will not be sent even after accepting the chat.
             let to_id = if curr_blocked == Blocked::Not
+                && !curr_hidden
                 && curr_param.get_bool(Param::WantsMdn).unwrap_or_default()
                 && curr_param.get_cmd() == SystemMessage::Unknown
                 && context.should_send_mdns().await?

src/reaction.rs

@@ -393,7 +393,9 @@ mod tests {
     use crate::chatlist::Chatlist;
     use crate::config::Config;
     use crate::contact::{Contact, Origin};
-    use crate::message::{MessageState, Viewtype, delete_msgs};
+    use crate::key::{load_self_public_key, load_self_secret_key};
+    use crate::message::{MessageState, Viewtype, delete_msgs, markseen_msgs};
+    use crate::pgp::{SeipdVersion, pk_encrypt};
     use crate::receive_imf::receive_imf;
     use crate::sql::housekeeping;
     use crate::test_utils::E2EE_INFO_MSGS;
@@ -956,4 +958,154 @@ Content-Disposition: reaction\n\
         }
         Ok(())
     }
+
+    /// Tests that if reaction requests a read receipt,
+    /// no read receipt is sent when the chat is marked as noticed.
+    ///
+    /// Reactions create hidden messages in the chat,
+    /// and when marking the chat as noticed marks
+    /// such messages as seen, read receipts should never be sent
+    /// to avoid the sender of reaction from learning
+    /// that receiver opened the chat.
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_reaction_request_mdn() -> Result<()> {
+        let mut tcm = TestContextManager::new();
+        let alice = &tcm.alice().await;
+        let bob = &tcm.bob().await;
+
+        let alice_chat_id = alice.create_chat_id(bob).await;
+        let alice_sent_msg = alice.send_text(alice_chat_id, "Hello!").await;
+
+        let bob_msg = bob.recv_msg(&alice_sent_msg).await;
+        bob_msg.chat_id.accept(bob).await?;
+        assert_eq!(bob_msg.state, MessageState::InFresh);
+        let bob_chat_id = bob_msg.chat_id;
+        bob_chat_id.accept(bob).await?;
+
+        markseen_msgs(bob, vec![bob_msg.id]).await?;
+        assert_eq!(
+            bob.sql
+                .count(
+                    "SELECT COUNT(*) FROM smtp_mdns WHERE from_id!=?",
+                    (ContactId::SELF,)
+                )
+                .await?,
+            1
+        );
+        bob.sql.execute("DELETE FROM smtp_mdns", ()).await?;
+
+        // Construct reaction with an MDN request.
+        // Note the `Chat-Disposition-Notification-To` header.
+        let known_id = bob_msg.rfc724_mid;
+        let new_id = "e2b6e69e-4124-4e2a-b79f-e4f1be667165@localhost";
+
+        let plain_text = format!(
+            "Content-Type: text/plain; charset=\"utf-8\"; protected-headers=\"v1\"; \r
+        hp=\"cipher\"\r
+Content-Disposition: reaction\r
+From: \"Alice\" <alice@example.org>\r
+To: \"Bob\" <bob@example.net>\r
+Subject: Message from Alice\r
+Date: Sat, 14 Mar 2026 01:02:03 +0000\r
+In-Reply-To: <{known_id}>\r
+References: <{known_id}>\r
+Chat-Version: 1.0\r
+Chat-Disposition-Notification-To: alice@example.org\r
+Message-ID: <{new_id}>\r
+HP-Outer: From: <alice@example.org>\r
+HP-Outer: To: \"hidden-recipients\": ;\r
+HP-Outer: Subject: [...]\r
+HP-Outer: Date: Sat, 14 Mar 2026 01:02:03 +0000\r
+HP-Outer: Message-ID: <{new_id}>\r
+HP-Outer: In-Reply-To: <{known_id}>\r
+HP-Outer: References: <{known_id}>\r
+HP-Outer: Chat-Version: 1.0\r
+Content-Transfer-Encoding: base64\r
+\r
+8J+RgA==\r
+"
+        );
+
+        let alice_public_key = load_self_public_key(alice).await?;
+        let bob_public_key = load_self_public_key(bob).await?;
+        let alice_secret_key = load_self_secret_key(alice).await?;
+        let public_keys_for_encryption = vec![alice_public_key, bob_public_key];
+        let compress = true;
+        let anonymous_recipients = true;
+        let encrypted_payload = pk_encrypt(
+            plain_text.as_bytes().to_vec(),
+            public_keys_for_encryption,
+            alice_secret_key,
+            compress,
+            anonymous_recipients,
+            SeipdVersion::V2,
+        )
+        .await?;
+
+        let boundary = "boundary123";
+        let rcvd_mail = format!(
+            "From: <alice@example.org>\r
+To: \"hidden-recipients\": ;\r
+Subject: [...]\r
+Date: Sat, 14 Mar 2026 01:02:03 +0000\r
+Message-ID: <{new_id}>\r
+In-Reply-To: <{known_id}>\r
+References: <{known_id}>\r
+Content-Type: multipart/encrypted; protocol=\"application/pgp-encrypted\";\r
+        boundary=\"{boundary}\"\r
+MIME-Version: 1.0\r
+\r
+--{boundary}\r
+Content-Type: application/pgp-encrypted; charset=\"utf-8\"\r
+Content-Description: PGP/MIME version identification\r
+Content-Transfer-Encoding: 7bit\r
+\r
+Version: 1\r
+\r
+--{boundary}\r
+Content-Type: application/octet-stream; name=\"encrypted.asc\";\r
+        charset=\"utf-8\"\r
+Content-Description: OpenPGP encrypted message\r
+Content-Disposition: inline; filename=\"encrypted.asc\";\r
+Content-Transfer-Encoding: 7bit\r
+\r
+{encrypted_payload}
+--{boundary}--\r
+"
+        );
+
+        let received = receive_imf(bob, rcvd_mail.as_bytes(), false)
+            .await?
+            .unwrap();
+        let bob_hidden_msg = Message::load_from_db(bob, *received.msg_ids.last().unwrap())
+            .await
+            .unwrap();
+        assert!(bob_hidden_msg.hidden);
+        assert_eq!(bob_hidden_msg.chat_id, bob_chat_id);
+
+        // Bob does not see new message and cannot mark it as seen directly,
+        // but can mark the chat as noticed when opening it.
+        marknoticed_chat(bob, bob_chat_id).await?;
+
+        assert_eq!(
+            bob.sql
+                .count(
+                    "SELECT COUNT(*) FROM smtp_mdns WHERE from_id!=?",
+                    (ContactId::SELF,)
+                )
+                .await?,
+            0,
+            "Bob should not send MDN to Alice"
+        );
+
+        // MDN request was ignored, but reaction was not.
+        let reactions = get_msg_reactions(bob, bob_msg.id).await?;
+        assert_eq!(reactions.reactions.len(), 1);
+        assert_eq!(
+            reactions.emoji_sorted_by_frequency(),
+            vec![("👀".to_string(), 1)]
+        );
+
+        Ok(())
+    }
 }

src/receive_imf.rs

@@ -1853,14 +1853,11 @@ async fn add_parts(
 
     let state = if !mime_parser.incoming {
         MessageState::OutDelivered
-    } else if seen
-        || !mime_parser.mdn_reports.is_empty()
-        || chat_id_blocked == Blocked::Yes
-        || group_changes.silent
+    } else if seen || !mime_parser.mdn_reports.is_empty() || chat_id_blocked == Blocked::Yes
     // No check for `hidden` because only reactions are such and they should be `InFresh`.
     {
         MessageState::InSeen
-    } else if mime_parser.from.addr == STATISTICS_BOT_EMAIL {
+    } else if mime_parser.from.addr == STATISTICS_BOT_EMAIL || group_changes.silent {
         MessageState::InNoticed
     } else {
         MessageState::InFresh

src/scheduler.rs

@@ -522,14 +522,6 @@ async fn fetch_idle(
         .await
         .context("download_msgs")?;
 
-    // Synchronize Seen flags.
-    session
-        .sync_seen_flags(ctx, &watch_folder)
-        .await
-        .context("sync_seen_flags")
-        .log_err(ctx)
-        .ok();
-
     connection.connectivity.set_idle(ctx);
 
     ctx.emit_event(EventType::ImapInboxIdle);