I recently wanted to install SharePoint Server 2013 October 2013 Cumulative Update (see Understanding the title information shown in SharePoint 2013 search and how to make it work better) and I was a little surprised to see that the Cumulative Updates for SharePoint 2013 requires you to install the SharePoint Server 2013 March 2013 Public Update (KB2767999) first.
If you install this update on a single server setup or on servers running search components, follow the steps outlined in How to install updated packages on a SharePoint farm where search component and high availability search topologies are enabled because this will help you speed up installation or use the PowerShell script shown in Why SharePoint 2013 Cumulative Update takes 5 hours to install? (Thanks Thomas Vochten for the tip :-) )
Remember though that Cumulative Updates typically contain fixes to address product and security defects as well as minor design change requests and are released every other month (on even months). Cumulative Updates are not tested as extensively as Service Packs and don’t typically undergo broad external testing, so they should always be tested in a non-production environment (but the same also applies to Service Packs). For the latest available updates see Update center for Office, Office Servers and related products .
Happy patching ….