diff --git a/td/telegram/OrderedMessage.cpp b/td/telegram/OrderedMessage.cpp
index 2c6569093..a092ed9ce 100644
--- a/td/telegram/OrderedMessage.cpp
+++ b/td/telegram/OrderedMessage.cpp
@@ -171,8 +171,8 @@ OrderedMessages::AttachInfo OrderedMessages::auto_attach_message(MessageId messa
   return {false, false};
 }
 
-static void do_find_older_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
-                                   vector<MessageId> &message_ids) {
+void OrderedMessages::do_find_older_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
+                                             vector<MessageId> &message_ids) {
   if (ordered_message == nullptr) {
     return;
   }
@@ -192,8 +192,8 @@ vector<MessageId> OrderedMessages::find_older_messages(MessageId max_message_id)
   return message_ids;
 }
 
-static void do_find_newer_messages(const OrderedMessage *ordered_message, MessageId min_message_id,
-                                   vector<MessageId> &message_ids) {
+void OrderedMessages::do_find_newer_messages(const OrderedMessage *ordered_message, MessageId min_message_id,
+                                             vector<MessageId> &message_ids) {
   if (ordered_message == nullptr) {
     return;
   }
@@ -213,8 +213,8 @@ vector<MessageId> OrderedMessages::find_newer_messages(MessageId min_message_id)
   return message_ids;
 }
 
-static MessageId do_find_message_by_date(const OrderedMessage *ordered_message, int32 date,
-                                         const std::function<int32(MessageId)> &get_message_date) {
+MessageId OrderedMessages::do_find_message_by_date(const OrderedMessage *ordered_message, int32 date,
+                                                   const std::function<int32(MessageId)> &get_message_date) {
   if (ordered_message == nullptr) {
     return MessageId();
   }
@@ -237,9 +237,9 @@ MessageId OrderedMessages::find_message_by_date(int32 date,
   return do_find_message_by_date(messages_.get(), date, get_message_date);
 }
 
-static void do_find_messages_by_date(const OrderedMessage *ordered_message, int32 min_date, int32 max_date,
-                                     const std::function<int32(MessageId)> &get_message_date,
-                                     vector<MessageId> &message_ids) {
+void OrderedMessages::do_find_messages_by_date(const OrderedMessage *ordered_message, int32 min_date, int32 max_date,
+                                               const std::function<int32(MessageId)> &get_message_date,
+                                               vector<MessageId> &message_ids) {
   if (ordered_message == nullptr) {
     return;
   }
@@ -263,9 +263,9 @@ vector<MessageId> OrderedMessages::find_messages_by_date(
   return message_ids;
 }
 
-static void do_traverse_messages(const OrderedMessage *ordered_message,
-                                 const std::function<bool(MessageId)> &need_scan_older,
-                                 const std::function<bool(MessageId)> &need_scan_newer) {
+void OrderedMessages::do_traverse_messages(const OrderedMessage *ordered_message,
+                                           const std::function<bool(MessageId)> &need_scan_older,
+                                           const std::function<bool(MessageId)> &need_scan_newer) {
   if (ordered_message == nullptr) {
     return;
   }
diff --git a/td/telegram/OrderedMessage.h b/td/telegram/OrderedMessage.h
index 69a46875d..2f04e75eb 100644
--- a/td/telegram/OrderedMessage.h
+++ b/td/telegram/OrderedMessage.h
@@ -14,16 +14,20 @@
 
 namespace td {
 
-struct OrderedMessage {
-  int32 random_y = 0;
+class OrderedMessage {
+ public:
+  MessageId message_id;
 
   bool have_previous = false;
   bool have_next = false;
 
-  MessageId message_id;
+ private:
+  int32 random_y = 0;
 
   unique_ptr<OrderedMessage> left;
   unique_ptr<OrderedMessage> right;
+
+  friend class OrderedMessages;
 };
 
 class OrderedMessages {
@@ -191,6 +195,23 @@ class OrderedMessages {
                          const std::function<bool(MessageId)> &need_scan_newer) const;
 
  private:
+  static void do_find_older_messages(const OrderedMessage *ordered_message, MessageId max_message_id,
+                                     vector<MessageId> &message_ids);
+
+  static void do_find_newer_messages(const OrderedMessage *ordered_message, MessageId min_message_id,
+                                     vector<MessageId> &message_ids);
+
+  static MessageId do_find_message_by_date(const OrderedMessage *ordered_message, int32 date,
+                                           const std::function<int32(MessageId)> &get_message_date);
+
+  static void do_find_messages_by_date(const OrderedMessage *ordered_message, int32 min_date, int32 max_date,
+                                       const std::function<int32(MessageId)> &get_message_date,
+                                       vector<MessageId> &message_ids);
+
+  static void do_traverse_messages(const OrderedMessage *ordered_message,
+                                   const std::function<bool(MessageId)> &need_scan_older,
+                                   const std::function<bool(MessageId)> &need_scan_newer);
+
   unique_ptr<OrderedMessage> messages_;
 };