Replication and Binary Logging Options and Variables or  Anonymous_gtid_log_event  if GTIDs are not in use on the server), and could be helpful in debugging cross-version replication issues. Setting the session value of this system variable is a restricted operation. The session user must have either the  REPLICATION_APPLIER  privilege (see Section 17.3.3, “Replication Privilege Checks” ), or privileges sufficient to set restricted session variables (see Section 5.1.9.1, “System Variable Privileges” ). However, note that the variable is not intended for users to set; it is set automatically by the replication infrastructure. For internal use by replication. This session system variable holds the MySQL Server release number of the server where a transaction was originally committed (for example,  80014  for a MySQL 8.0.14 server instance). If this original server is at a release that does not support the session system variable, the value of the variable is set to 0 ( UNKNOWN_SERVER_VERSION ). Note that when a release number is set by the original server, the value of the variable is reset to 0 if the immediate server or any other intervening server in the replication topology does not support the session system variable, and so does not replicate its value. The value of the variable is set and used in the same ways as for the  immediate_server_version system variable. If the value of the variable is the same as that for the  immediate_server_version system variable, only the latter is recorded in the binary log, with an indicator that the original server version is the same. In a Group Replication environment, view change log events, which are special transactions queued by each group member when a new member joins the group, are tagged with the server version of the group member queuing the transaction. This ensures that the server version of the original donor is known to the joining member. Because the view change log events queued for a particular view change have the same GTID on all members, for this case only, instances of the same GTID might have a different original server version. Setting the session value of this system variable is a restricted operation. The session user must have either the  REPLICATION_APPLIER  privilege (see Section 17.3.3, “Replication Privilege Checks” ), or privileges sufficient to set restricted session variables (see Section 5.1.9.1, “System Variable Privileges” ). However, note that the variable is not intended for users to set; it is set automatically by the replication infrastructure. 3501 • rpl_semi_sync_master_enabled • original_server_version Introduced 8.0.14 System Variable original_server_version Scope Session Dynamic Yes SET_VAR  Hint Applies No Type Integer Command-Line Format --rpl-semi-sync-master-enabled[={OFF| ON}] System Variable rpl_semi_sync_master_enabled Scope Global Dynamic Yes