I need to add an SQL-feature (SQL-replication) to an existing SQL-instance. It's SQL Server 2012 Standard SP1 that has been upgraded to SP3 a few years ago.
What installation media should I use to add the SQL-feature?
SQL Server 2012 Std with SP1 or SQL Server 2012 Std with SP3?
Or can I add it by installing the SP3 again somehow?
You can add a feature with the base media for 2012 Standard by running setup and choosing that feature, then, once it completes, you can run the Service Pack install and/or cumulative updates to get it to the current level of the features and engine installed.
I got a recommendation from an SQL-expert that I really should use the SQL Server 2012 Std with SP3.
And it worked like a charm :)