MaxScale fails to start on upgrade if deprecated options are in the db config table.

After upgrade for example from 22.08 to 25.01.6 starting maxscale fails with:

2026-03-27 13:31:34   error  : (ConfigManager); readwritesplit: The parameter 'optimistic_trx' is unrecognized.

2026-03-27 13:31:34   error  : (ConfigManager); readwritesplit: The parameter 'reuse_prepared_statements' is unrecognized.

2026-03-27 13:31:34   error  : (ConfigManager); Could not create service 'Read-Write-Service' with module 'readwritesplit'

To overcome this we had to manually remove the parameters from the JSON object via a stored procedure.

Also after fixing the above parameters another issue arised, Maxscale reported skip_permission_checks as unrecognized, even though it wasn’t explicitly set. After manually setting it to null it started.

I guess maxscale upgrade should take care of removing the deprecated options for the json object on a pre-flight check upon restart or ignore deprecated options, a post upgrade script would require db connection parameters imho a bit not elegant.