Starting with CRM 2015, Microsoft has changed the naming convention for CRM updates as described in this article, http://blogs.msdn.com/b/crm/archive/2015/04/14/new-naming-conventions-for-microsoft-dynamics-crm-updates.aspx.
In the past we've had Update Rollups, Service Packs and various names for updates to CRM Online.
It's all down to the version number. You can find the version number of your CRM build in the web client, by clicking the Settings icon at the top right and then clicking About. The version number has four parts, for example: 126.96.36.1999
In an effort to unify the naming convention, the following applies:
- The first number in the version is the major release. CRM 2015 is major release number 7, CRM 2013 is major release 6 and so on.
- The second number is the minor release. For example, the Leo release for CRM 2013 was minor release 1, so the version number was 6.1.0.xxx. In CRM 2013 On-premise whis was called a service pack. Only one service pack was released.
- The third number is the minor incremental update. This is equivalent to Update Rollups in CRM on-premise.
- The fourth number is the build. We need not be concerned with the build number, it is incremented each time the CRM developers make a change to CRM code.
Note that not all updates made available for CRM Online are released for CRM On-premise so you might see a gap in version numbers. For example, the Spring 2015 "Carina" release for CRM Online is not planned to be released for CRM On-premise. So the version numbering will as per the table, note the "Not Released" entries.