diff --git a/src/rootserver/backup/ob_tenant_archive_scheduler.cpp b/src/rootserver/backup/ob_tenant_archive_scheduler.cpp
index 10d74fb5e4..5cffe32d7f 100644
--- a/src/rootserver/backup/ob_tenant_archive_scheduler.cpp
+++ b/src/rootserver/backup/ob_tenant_archive_scheduler.cpp
@@ -134,7 +134,6 @@ static int record_piece_checkpoint(const ObTenantArchivePieceAttr &piece_info, c
     && ObBackupFileStatus::STATUS::BACKUP_FILE_AVAILABLE == piece_info.file_status_)) {
   } else {
     // persist piece checkpoint
-    // TODO: change overwrite to append
     ObPieceCheckpointDesc checkpoint_desc;
     checkpoint_desc.tenant_id_ = piece_info.key_.tenant_id_;
     checkpoint_desc.dest_id_ = piece_info.key_.dest_id_;
diff --git a/src/share/backup/ob_archive_store.h b/src/share/backup/ob_archive_store.h
index 4cfc71fce9..9cdaa22933 100644
--- a/src/share/backup/ob_archive_store.h
+++ b/src/share/backup/ob_archive_store.h
@@ -222,7 +222,6 @@ public:
   int64_t piece_id_;
   int64_t incarnation_;
   ObArchiveCompatible compatible_;
-  // TODO: scn type need provide serialize method which returns fixed length.
   SCN start_scn_; // archive start time of the round
   SCN checkpoint_scn_; // archive end time of the round
   SCN max_scn_;
diff --git a/src/share/backup/ob_archive_struct.h b/src/share/backup/ob_archive_struct.h
index 6279d19193..4948f45cee 100644
--- a/src/share/backup/ob_archive_struct.h
+++ b/src/share/backup/ob_archive_struct.h
@@ -29,8 +29,6 @@ namespace share
 // Initial round id for new round.
 const int64_t OB_START_LOG_ARCHIVE_ROUND_ID = 0;
 
-// TODO: replace to real scn type later.
-
 // archive state machine
 struct ObArchiveRoundState
 {
diff --git a/src/share/backup/ob_backup_connectivity.cpp b/src/share/backup/ob_backup_connectivity.cpp
index 1dc36eb9fe..002bd92ae1 100644
--- a/src/share/backup/ob_backup_connectivity.cpp
+++ b/src/share/backup/ob_backup_connectivity.cpp
@@ -360,8 +360,6 @@ int ObBackupCheckFile::generate_format_desc_(const share::ObBackupDest &dest, sh
   schema::ObSchemaGetterGuard schema_guard;
   const schema::ObTenantSchema *tenant_schema = nullptr;
 
-  // TODO: pass GCONF and GCTX to class.
-
   if (OB_ISNULL(GCTX.schema_service_)) {
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("invalid argument", K(ret), K(GCTX.schema_service_));
diff --git a/src/share/backup/ob_backup_serialize_provider.h b/src/share/backup/ob_backup_serialize_provider.h
index b2caec6527..944225c46b 100644
--- a/src/share/backup/ob_backup_serialize_provider.h
+++ b/src/share/backup/ob_backup_serialize_provider.h
@@ -38,7 +38,6 @@ public:
 
 
 // Wrapper backup serialize data with common backup header.
-  // TODO: support deserialize according to different version.
 class ObBackupSerializeHeaderWrapper final : public ObIBackupSerializeProvider
 {
 public:
diff --git a/src/share/backup/ob_backup_store.cpp b/src/share/backup/ob_backup_store.cpp
index 9a4d7cefd5..83e0de67d5 100644
--- a/src/share/backup/ob_backup_store.cpp
+++ b/src/share/backup/ob_backup_store.cpp
@@ -487,7 +487,7 @@ int ObBackupDestMgr::generate_format_desc_(
   schema::ObSchemaGetterGuard schema_guard;
   share::ObBackupPathString root_path;
   const schema::ObTenantSchema *tenant_schema = nullptr;
-  // TODO: pass GCONF and GCTX to class.
+
   if (OB_ISNULL(GCTX.schema_service_)) {
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("invalid argument", K(ret), K(GCTX.schema_service_));
diff --git a/src/storage/backup/ob_backup_utils.cpp b/src/storage/backup/ob_backup_utils.cpp
index ed257cbfa8..209ed51808 100755
--- a/src/storage/backup/ob_backup_utils.cpp
+++ b/src/storage/backup/ob_backup_utils.cpp
@@ -1896,7 +1896,6 @@ int ObBackupTabletProvider::get_tablet_handle_(const uint64_t tenant_id, const s
             LOG_INFO("transfer table is not replaced", K(ret), K(tenant_id), K(ls_id), K(tablet_id));
             usleep(100 * 1000); // wait 100ms
           } else {
-            // TODO:(wangxiaohui.wxh): make sure clog checkpoint scn of tablet is over consistent_scn
             break;
           }
         }
diff --git a/src/storage/high_availability/ob_storage_ha_reader.cpp b/src/storage/high_availability/ob_storage_ha_reader.cpp
index 2825ed04bb..f3b234c7bb 100644
--- a/src/storage/high_availability/ob_storage_ha_reader.cpp
+++ b/src/storage/high_availability/ob_storage_ha_reader.cpp
@@ -1369,8 +1369,7 @@ int ObCopySSTableInfoRestoreReader::get_next_tablet_sstable_header(
     sstable_index_ = 0;
     is_sstable_iter_end_ = true;
     copy_header.sstable_count_ = 0;
-    // TODO(wangxiaohui.wxh): to correct the version
-    copy_header.version_ = 0; // restore version is not valid
+    copy_header.version_ = restore_base_info_->backup_cluster_version_;
     tablet_index_++;
   } else if (OB_FAIL(get_backup_sstable_metas_(tablet_id))) {
     LOG_WARN("failed to get backup sstable metas", K(ret), K(tablet_id), KPC(restore_base_info_));
@@ -1378,7 +1377,7 @@ int ObCopySSTableInfoRestoreReader::get_next_tablet_sstable_header(
     sstable_index_ = 0;
     is_sstable_iter_end_ = backup_sstable_meta_array_.count() > 0 ? false : true;
     copy_header.sstable_count_ = backup_sstable_meta_array_.count();
-    copy_header.version_ = 0; // restore version is not valid
+    copy_header.version_ = restore_base_info_->backup_cluster_version_;
     tablet_index_++;
   }
   return ret;
diff --git a/src/storage/high_availability/ob_transfer_backfill_tx.cpp b/src/storage/high_availability/ob_transfer_backfill_tx.cpp
index bd85d4a1a1..e6e1871950 100644
--- a/src/storage/high_availability/ob_transfer_backfill_tx.cpp
+++ b/src/storage/high_availability/ob_transfer_backfill_tx.cpp
@@ -1543,7 +1543,6 @@ int ObTransferReplaceTableTask::check_tablet_after_replace_(ObLS *ls, const comm
     LOG_WARN("fetch table store fail", K(ret), KPC(tablet));
   } else if (tablet->get_tablet_meta().ha_status_.is_restore_status_full()
              && wrapper.get_member()->get_major_sstables().empty()) {
-    // TODO(wangxiaohui.wxh), consider index tablet, major is generated when replay commit log.
     // In case of restore, if restore status is FULL, major sstable must be exist after replace.
     ret = OB_INVALID_TABLE_STORE;
     LOG_WARN("tablet should be exist major sstable", K(ret), KPC(tablet));
diff --git a/src/storage/ls/ob_ls.cpp b/src/storage/ls/ob_ls.cpp
index 1fd2f05697..95c049008c 100755
--- a/src/storage/ls/ob_ls.cpp
+++ b/src/storage/ls/ob_ls.cpp
@@ -1808,7 +1808,7 @@ int ObLS::get_ls_meta_package_and_tablet_metas(
   } else if (OB_FAIL(tablet_gc_handler_.disable_gc())) {
     LOG_WARN("failed to disable gc", K(ret), "ls_id", ls_meta_.ls_id_);
   } else {
-    // TODO(wangxiaohui.wxh) consider the ls is offline meanwhile.
+    // TODO(wangxiaohui.wxh) 4.3, consider the ls is offline meanwhile.
     // disable gc while get all tablet meta
     ObLSMetaPackage meta_package;
     if (OB_FAIL(get_ls_meta_package(check_archive, meta_package))) {
diff --git a/src/storage/ob_storage_rpc.h b/src/storage/ob_storage_rpc.h
index fdda33aa1f..b750057155 100755
--- a/src/storage/ob_storage_rpc.h
+++ b/src/storage/ob_storage_rpc.h
@@ -348,7 +348,7 @@ public:
   storage::ObCopyTabletStatus::STATUS status_;
   int64_t sstable_count_;
   ObMigrationTabletParam tablet_meta_;
-  uint64_t version_;
+  uint64_t version_; // source observer version.
 };
 
 // Leader notify follower to restore some tablets.
diff --git a/src/storage/restore/ob_ls_restore_handler.cpp b/src/storage/restore/ob_ls_restore_handler.cpp
index 0d50d277f4..7fd9c4fe0a 100644
--- a/src/storage/restore/ob_ls_restore_handler.cpp
+++ b/src/storage/restore/ob_ls_restore_handler.cpp
@@ -2164,7 +2164,7 @@ int ObLSQuickRestoreState::leader_quick_restore_()
   }
 
 #if 0
-  // TODO(wangxiaohui.wxh): let leader restore from backup and follower restore from leader.
+  // TODO(wangxiaohui.wxh): 4.3, let leader restore from backup and follower restore from leader.
 
   int tmp_ret = OB_SUCCESS; // try rpc's best
   if (restored_tablets.empty()) {
@@ -2233,7 +2233,7 @@ int ObLSQuickRestoreState::do_quick_restore_(const ObLSRestoreTaskMgr::ToRestore
   }
 
 #if 0
-  // TODO(wangxiaohui.wxh): let leader restore from backup and follower restore from leader.
+  // TODO(wangxiaohui.wxh): 4.3, let leader restore from backup and follower restore from leader.
   if (!is_follower(role_)
       || tablet_need_restore.action() == ObTabletRestoreAction::ACTION::RESTORE_TABLET_META) {
     if (OB_FAIL(leader_fill_tablet_group_restore_arg_(tablet_need_restore.get_tablet_list(), tablet_need_restore.action(), arg))) {
diff --git a/src/storage/restore/ob_ls_restore_task_mgr.cpp b/src/storage/restore/ob_ls_restore_task_mgr.cpp
index eb7836b898..2fee2cc3b0 100644
--- a/src/storage/restore/ob_ls_restore_task_mgr.cpp
+++ b/src/storage/restore/ob_ls_restore_task_mgr.cpp
@@ -781,7 +781,7 @@ int ObLSRestoreTaskMgr::check_need_discard_transfer_tablet_(
         // overwrite error code if transfer start has stepped into 2-phase transaction before recover finished.
         ret = OB_SUCCESS;
       } else {
-        // TODO(wangxiaohui.wxh): cannot let restore failed if restore_scn is between prepare and commit.
+        // TODO(wangxiaohui.wxh): 4.3, cannot let restore failed if restore_scn is between prepare and commit.
       }
     } else {
       LOG_WARN("fail to check transfer start finish", K(ret), K_(ls_id), K(tablet_handle));