On December 18, 2017, Microsoft released SQL Server 2014 SP2 CU9, which is Build 12.05563.0. By my count, this CU has seven public hotfixes, nearly all of which are for the SQL Engine of SQL performance.

Since SQL Server 2014 SP1 and earlier are no longer “supported service packs”, there is no corresponding CU for the SP1 or RTM branches of SQL Server 2014.

As always, I think it is a good idea to make an effort to stay current on cumulative updates, as does Microsoft.