Merge pull request #267565 from kabharati/patch-186

Update concepts-backup-restore.md

Author: prmerger-automator[bot]

articles/postgresql/flexible-server/concepts-backup-restore.md

@@ -184,6 +184,7 @@ Azure Backup and Azure Database for PostgreSQL flexible server services have bui
 
 - In preview, LTR restore is currently available as RestoreasFiles to storage accounts. RestoreasServer capability will be added in the future.
 - In preview, you can perform LTR backups for all databases, single db backup support will be added in the future.
+- LTR backup is currently not supported for CMK-enabled servers. This capability will be added in the future.
 
 
 For more information about performing a long term backup, visit the [how-to guide](../../backup/backup-azure-database-postgresql-flex.md).