The following table details updates (depending on version might be called update rollup or service pack) for Microsoft Dynamics 365/CRM. Note that some updates cannot be installed, so a backup before installation is advised. Click on the Build Number for more details.

This article, https://support.microsoft.com/en-us/kb/2925359, lists updates applied to CRM Online.

New naming convention for updates starting with CRM 2015

Microsoft changed the naming convention for updates in this article, http://blogs.msdn.com/b/crm/archive/2015/04/14/new-naming-conventions-fo.... No more Update Rollups or Service Packs, just Updates.

Build Number

For CRM 2013 onwards, the third number in the build is the same as the Update Rollup number.

A separate set of update rollups is released for CRM 2013 and CRM 2013 with SP1. Confused? See this article http://www.fkbase.info/crm2013UpdateRollups.

For more information refer to this blog: http://blogs.msdn.com/b/crminthefield/

For more details on compatibility with other Microsoft products, review this article, http://support.microsoft.com/kb/2669061.

This article https://support.microsoft.com/kb/3036179 shows links for installations, updates and documentation for CRM versions since 4.0.