ActiveRecord::StatementInvalid: PG::UndefinedColumn: ERROR: column categories.search_priority does not exist

Adding the multisite:migrate line is part of the howto for multisite setups

Using the multisite:migrate command as described in the howto :wink:

This is certainly surprising. I think you would be noticing issues if you hadn’t migrated for a whole year. If it was only a few weeks, then it might be possible to continue running on an old schema without too many errors. Have you modified one of the other templates to include multisite:migrate?