diff --git a/td/telegram/MessagesManager.cpp b/td/telegram/MessagesManager.cpp
index 1554dec22..a1c5da614 100644
--- a/td/telegram/MessagesManager.cpp
+++ b/td/telegram/MessagesManager.cpp
@@ -11625,21 +11625,6 @@ vector<MessageId> MessagesManager::find_dialog_messages(const Dialog *d,
   return message_ids;
 }
 
-void MessagesManager::find_old_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
-                                        vector<MessageId> &message_ids) {
-  if (ordered_message == nullptr) {
-    return;
-  }
-
-  find_old_messages(ordered_message->left.get(), max_message_id, message_ids);
-
-  if (ordered_message->message_id <= max_message_id) {
-    message_ids.push_back(ordered_message->message_id);
-
-    find_old_messages(ordered_message->right.get(), max_message_id, message_ids);
-  }
-}
-
 void MessagesManager::find_newer_messages(const OrderedMessage *ordered_message, MessageId min_message_id,
                                           vector<MessageId> &message_ids) {
   if (ordered_message == nullptr) {
@@ -13072,8 +13057,7 @@ void MessagesManager::set_dialog_max_unavailable_message_id(DialogId dialog_id,
 
     d->max_unavailable_message_id = max_unavailable_message_id;
 
-    vector<MessageId> message_ids;
-    find_old_messages(d->ordered_messages.messages_.get(), max_unavailable_message_id, message_ids);
+    auto message_ids = d->ordered_messages.find_older_messages(max_unavailable_message_id);
 
     vector<int64> deleted_message_ids;
     bool need_update_dialog_pos = false;
diff --git a/td/telegram/MessagesManager.h b/td/telegram/MessagesManager.h
index d9c53712f..8603e212d 100644
--- a/td/telegram/MessagesManager.h
+++ b/td/telegram/MessagesManager.h
@@ -2185,9 +2185,6 @@ class MessagesManager final : public Actor {
   static void find_messages_by_date(const Dialog *d, const OrderedMessage *ordered_message, int32 min_date,
                                     int32 max_date, vector<MessageId> &message_ids);
 
-  static void find_old_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
-                                vector<MessageId> &message_ids);
-
   static void find_newer_messages(const OrderedMessage *ordered_message, MessageId min_message_id,
                                   vector<MessageId> &message_ids);
 
diff --git a/td/telegram/OrderedMessage.cpp b/td/telegram/OrderedMessage.cpp
index 038b264e9..55989087f 100644
--- a/td/telegram/OrderedMessage.cpp
+++ b/td/telegram/OrderedMessage.cpp
@@ -77,4 +77,25 @@ void OrderedMessages::erase(MessageId message_id) {
   CHECK(*v == nullptr);
 }
 
+static void do_find_older_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
+                                   vector<MessageId> &message_ids) {
+  if (ordered_message == nullptr) {
+    return;
+  }
+
+  do_find_older_messages(ordered_message->left.get(), max_message_id, message_ids);
+
+  if (ordered_message->message_id <= max_message_id) {
+    message_ids.push_back(ordered_message->message_id);
+
+    do_find_older_messages(ordered_message->right.get(), max_message_id, message_ids);
+  }
+}
+
+vector<MessageId> OrderedMessages::find_older_messages(MessageId max_message_id) const {
+  vector<MessageId> message_ids;
+  do_find_older_messages(messages_.get(), max_message_id, message_ids);
+  return message_ids;
+}
+
 }  // namespace td
diff --git a/td/telegram/OrderedMessage.h b/td/telegram/OrderedMessage.h
index 35596b937..2af59cff5 100644
--- a/td/telegram/OrderedMessage.h
+++ b/td/telegram/OrderedMessage.h
@@ -30,6 +30,8 @@ struct OrderedMessages {
   OrderedMessage *insert(MessageId message_id);
 
   void erase(MessageId message_id);
+
+  vector<MessageId> find_older_messages(MessageId max_message_id) const;
 };
 
 }  // namespace td