SQL Server build and update nomenclature

SQL Server build and update nomenclature is more complex than anyone would like.

Release Candidate (RC) is the Beta version of a release and should not be used in production.

Release to Manufacture (RTM) is the Initial production release after RC (Beta) version.

General Distribution Release (GDR) is a kind of hotfix or patch that contains specific fixes and is intended for installation on all SQL instances. It addresses an issue that has a broad customer impact, security implications, or both. If you want to apply only security updates, stay on GDR releases. If you want to get additional fixes, use CU releases.

Service Packs (SP) Prior to SQL Server 2017 Microsoft distributed fixes in Service Packs. Service Packs include hotfixes and fixes to issues that are reported through the Microsoft SQL Server community. Service Packs may also include issues that Microsoft’s? support organization feels must be addressed. SQL Server 2017 and later versions no longer receive Service Packs.

Cumulative Update (CU) is a collection of hot fixes released after Service Pack (prior to SQL Server 2017). Starting with SQL Server 2017 all updates are addressed by CUs or GDRs. A CU contains all previous hotfixes to date and includes both security fixes and functional fixes.