diff --git a/python/tests/test_4_lowlevel.py b/python/tests/test_4_lowlevel.py
index 23ef3dbe3..4d9865ec6 100644
--- a/python/tests/test_4_lowlevel.py
+++ b/python/tests/test_4_lowlevel.py
@@ -156,6 +156,8 @@ def test_markseen_invalid_message_ids(acfactory):
     chat = contact1.create_chat()
     chat.send_text("one message")
     ac1._evtracker.get_matching("DC_EVENT_MSGS_CHANGED")
+    # Skip configuration-related warnings, but not errors.
+    ac1._evtracker.ensure_event_not_queued("DC_EVENT_ERROR")
     msg_ids = [9]
     lib.dc_markseen_msgs(ac1._dc_context, msg_ids, len(msg_ids))
     ac1._evtracker.ensure_event_not_queued("DC_EVENT_WARNING|DC_EVENT_ERROR")
diff --git a/src/config.rs b/src/config.rs
index 192b4e25c..a71f3ca53 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -356,7 +356,10 @@ impl Config {
     /// multiple users are sharing an account. Another example is `Self::SyncMsgs` itself which
     /// mustn't be controlled by other devices.
     pub(crate) fn is_synced(&self) -> bool {
-        matches!(self, Self::MdnsEnabled | Self::ShowEmails)
+        matches!(
+            self,
+            Self::Displayname | Self::MdnsEnabled | Self::ShowEmails
+        )
     }
 }
 
@@ -487,8 +490,9 @@ impl Context {
         &self,
         sync: sync::Sync,
         key: Config,
-        value: Option<&str>,
+        mut value: Option<&str>,
     ) -> Result<()> {
+        let better_value;
         match key {
             Config::Selfavatar => {
                 self.sql
@@ -515,10 +519,11 @@ impl Context {
                 ret?
             }
             Config::Displayname => {
-                let value = value.map(improve_single_line_input);
-                self.sql
-                    .set_raw_config(key.as_ref(), value.as_deref())
-                    .await?;
+                if let Some(v) = value {
+                    better_value = improve_single_line_input(v);
+                    value = Some(&better_value);
+                }
+                self.sql.set_raw_config(key.as_ref(), value).await?;
             }
             Config::Socks5Enabled
             | Config::BccSelf
@@ -873,16 +878,6 @@ mod tests {
             mdns_enabled
         );
 
-        // Usual sync scenario.
-        alice0
-            .set_config_bool(Config::MdnsEnabled, !mdns_enabled)
-            .await?;
-        sync(&alice0, &alice1).await?;
-        assert_eq!(
-            alice1.get_config_bool(Config::MdnsEnabled).await?,
-            !mdns_enabled
-        );
-
         // Reset to default. Test that it's not synced because defaults may differ across client
         // versions.
         alice0.set_config(Config::MdnsEnabled, None).await?;
@@ -908,6 +903,16 @@ mod tests {
         sync(&alice0, &alice1).await?;
         assert!(alice1.get_config_bool(Config::MdnsEnabled).await?);
 
+        // Usual sync scenario.
+        alice0
+            .set_config(Config::Displayname, Some("Alice Sync"))
+            .await?;
+        sync(&alice0, &alice1).await?;
+        assert_eq!(
+            alice1.get_config(Config::Displayname).await?,
+            Some("Alice Sync".to_string())
+        );
+
         Ok(())
     }
 }
diff --git a/src/receive_imf.rs b/src/receive_imf.rs
index f5374015c..baa1578ff 100644
--- a/src/receive_imf.rs
+++ b/src/receive_imf.rs
@@ -451,7 +451,10 @@ pub(crate) async fn receive_imf_inner(
 ///
 /// Also returns whether it is blocked or not and its origin.
 ///
-/// * `prevent_rename`: passed through to `add_or_lookup_contacts_by_address_list()`
+/// * `prevent_rename`: if true, the display_name of this contact will not be changed. Useful for
+/// mailing lists: In some mailing lists, many users write from the same address but with different
+/// display names. We don't want the display name to change every time the user gets a new email from
+/// a mailing list.
 ///
 /// Returns `None` if From field does not contain a valid contact address.
 pub async fn from_field_to_contact_id(
@@ -2600,11 +2603,6 @@ pub(crate) async fn get_prefetch_parent_message(
 /// Looks up contact IDs from the database given the list of recipients.
 ///
 /// Returns vector of IDs guaranteed to be unique.
-///
-/// * param `prevent_rename`: if true, the display_name of this contact will not be changed. Useful for
-/// mailing lists: In some mailing lists, many users write from the same address but with different
-/// display names. We don't want the display name to change every time the user gets a new email from
-/// a mailing list.
 async fn add_or_lookup_contacts_by_address_list(
     context: &Context,
     address_list: &[SingleInfo],