Solution Systems hosts many versions of Microsoft Dynamics CRM to meet its customers' various needs, including Microsoft Dynamics CRM 2013 with Service Pack 1 (SP1). We will soon be applying Update Rollup 2 to those instances.
Update Rollup 2 for Microsoft Dynamics CRM 2013 Service Pack 1 (SP1) was originally announced in a pre-release article in November, 2014. It's finally available in February 2015, and it was worth the wait. It fixes many issues; the Microsoft knowledge base article lists 153 (see link below)
If you have CRM online, and have not opted in to upgrade to the 2015 version, you will effectively remain in the 2013 (SP1) version and should automatically get the equivalent code to Update Rollup 2 when Microsoft deploys it to the CRM Online servers. Note that CRM Online has its own code update stream with updates that are similar to, but not necessarily exactly matching the ones described in the knowledge base articles for on-premises and partner-hosted servers. Microsoft typically does not announce its CRM Online updates unless there's major version change, such as 2015.
Knowledge base article: http://support2.microsoft.com/default.aspx?kbid=2963850