diff --git a/crates/jmap/src/participant_identity/set.rs b/crates/jmap/src/participant_identity/set.rs
index 32e387c4..bfe6a530 100644
--- a/crates/jmap/src/participant_identity/set.rs
+++ b/crates/jmap/src/participant_identity/set.rs
@@ -199,7 +199,6 @@ fn validate_identity_value(
     identity: &mut ParticipantIdentity,
     allowed_emails: &AHashSet<String>,
 ) -> Result<(), SetError<ParticipantIdentityProperty>> {
-    let mut changed_address = None;
     for (property, value) in update.into_expanded_object() {
         let Key::Property(property) = property else {
             return Err(SetError::invalid_properties()
@@ -213,7 +212,27 @@ fn validate_identity_value(
             }
             (ParticipantIdentityProperty::CalendarAddress, Value::Str(value)) => {
                 if identity.calendar_address != value {
-                    changed_address = Some(value);
+                    let email = if let Some(email) = value.strip_prefix("mailto:") {
+                        sanitize_email(email)
+                    } else {
+                        sanitize_email(&value)
+                    };
+
+                    if let Some(email) = email {
+                        if allowed_emails.iter().any(|e| e == &email) {
+                            identity.calendar_address = format!("mailto:{email}");
+                        } else {
+                            return Err(SetError::invalid_properties()
+                                .with_property(ParticipantIdentityProperty::CalendarAddress)
+                                .with_description(
+                                    "Calendar address not configured for this account.".to_string(),
+                                ));
+                        }
+                    } else {
+                        return Err(SetError::invalid_properties()
+                            .with_property(ParticipantIdentityProperty::CalendarAddress)
+                            .with_description("Invalid or missing calendar address.".to_string()));
+                    }
                 }
             }
             (property, _) => {
@@ -223,34 +242,10 @@ fn validate_identity_value(
             }
         }
     }
+
     // Validate email address
     if !identity.calendar_address.is_empty() {
-        if let Some(new_address) = changed_address {
-            let email = if let Some(email) = new_address.strip_prefix("mailto:") {
-                sanitize_email(email)
-            } else {
-                sanitize_email(&new_address)
-            };
-
-            if let Some(email) = email {
-                if allowed_emails.iter().any(|e| e == &email) {
-                    identity.calendar_address = format!("mailto:{email}");
-                    Ok(())
-                } else {
-                    Err(SetError::invalid_properties()
-                        .with_property(ParticipantIdentityProperty::CalendarAddress)
-                        .with_description(
-                            "Calendar address not configured for this account.".to_string(),
-                        ))
-                }
-            } else {
-                Err(SetError::invalid_properties()
-                    .with_property(ParticipantIdentityProperty::CalendarAddress)
-                    .with_description("Invalid or missing calendar address.".to_string()))
-            }
-        } else {
-            Ok(())
-        }
+        Ok(())
     } else {
         Err(SetError::invalid_properties()
             .with_property(ParticipantIdentityProperty::CalendarAddress)
diff --git a/crates/store/src/query/log.rs b/crates/store/src/query/log.rs
index fe03dbe4..2e4bd303 100644
--- a/crates/store/src/query/log.rs
+++ b/crates/store/src/query/log.rs
@@ -63,14 +63,14 @@ impl Store {
     pub async fn changes(
         &self,
         account_id: u32,
-        collection: LogCollection,
+        collection_: LogCollection,
         query: Query,
     ) -> trc::Result<Changes> {
         let is_share_log = matches!(
-            collection,
+            collection_,
             LogCollection::Sync(SyncCollection::ShareNotification)
         );
-        let collection = u8::from(collection);
+        let collection = u8::from(collection_);
 
         let (is_inclusive, from_change_id, to_change_id) = match query {
             Query::All => (true, 0, u64::MAX),
@@ -127,13 +127,13 @@ impl Store {
         .await
         .caused_by(trc::location!())?;
 
-        if changelog.changes.is_empty() {
-            changelog.from_change_id = from_change_id;
-            changelog.to_change_id = if to_change_id != u64::MAX {
-                to_change_id
-            } else {
-                from_change_id
-            };
+        // A non-existing change id was requested, return the last change id
+        if changelog.changes.is_empty() && from_change_id != 0 && changelog.from_change_id == 0 {
+            changelog.from_change_id = self
+                .get_last_change_id(account_id, collection_)
+                .await?
+                .unwrap_or_default();
+            changelog.to_change_id = changelog.from_change_id;
         }
 
         Ok(changelog)