22:11:18: ERROR[EmergeThread0]: Invalid block data in database (0,-1933,0) (SerializationError): unsupported NameIdMapping version
22:11:18: ACTION[ServerThread]: Updated online player file
22:11:25: ERROR[EmergeThread0]: Invalid block data in database (0,-1933,0) (SerializationError): unsupported NameIdMapping version
22:11:27: ERROR[main]: ERROR: An unhandled exception occurred: Invalid data in MapBlock (0,-1933,0)
22:11:27: ERROR[main]: ----
22:11:27: ERROR[main]: "Invalid block data in database"
22:11:28: ERROR[main]: See debug.txt.
22:11:28: ERROR[main]: You can ignore this using [ignore_world_load_errors = true].
I have added ignore_world_load_errors = true into the config but I'd rather fix the problem so that the server window stops getting clogged up with error messages.