When Updating from a version < 3.4.0 to a version >= 3.4.0, it must be ensured that when using a database metaservice that there are not multiple content servers using the same database.
With version 3.4.0 a change in the database structure was made, which is not compatible with prior versions. The database change is done automatically upon first start. The parallel usage of the same database with multiple tia core server instances with version < 3.4.0 and version >= 3.4.0 is therefor not possible.