Here are the Knowledgebase Articles available for Symantec Endpoint Protection 12.1.4013 (RU4) which would assist you to prepare for this Latest Release.
NOTE: This Article would be updated as and when new Articles in reference to Symantec Endpoint Protection 12.1.4013 (RU4) gets published.
Product Guides
Release Notes and System Requirements for all versions of Symantec Endpoint Protection and Symantec Network Access Control
http://www.symantec.com/docs/TECH163829
Symantec Endpoint Protection, Symantec Endpoint Protection Small Business Edition, and Symantec Network Access Control 12.1.4 Release Notes/What’s New
http://www.symantec.com/docs/DOC6838
System Requirements for Symantec Endpoint Protection, Enterprise and Small Business Editions, and Network Access Control 12.1.4
http://www.symantec.com/docs/TECH212063
Installation and Getting Started.
New fixes and features in Symantec Endpoint Protection 12.1.4
http://www.symantec.com/docs/TECH211972
Best practices for upgrading to Symantec Endpoint Protection 12.1.x
http://www.symantec.com/business/support/index?page=content&id=TECH163700
Upgrading or migrating to Symantec Endpoint Protection 12.1.4 (RU4)
http://www.symantec.com/docs/TECH211821
Overview for Symantec Endpoint Protection 12.1.4 for Mac
http://www.symantec.com/docs/HOWTO92146
What are the officially released versions of Symantec Endpoint Protection (SEP)?
http://www.symantec.com/docs/TECH154475
Third-party security software removal support in Symantec Endpoint Protection 12.1.2 and later
http://www.symantec.com/docs/TECH195029
About Windows 8 and Symantec Endpoint Protection 12.1
http://www.symantec.com/docs/TECH174348
Information about the "Fast-Pathing" feature in SEP 12.1 RU4
http://www.symantec.com/docs/TECH212153
Compatibility between Symantec Endpoint Protection for Mac/Symantec AntiVirus for Macintosh and versions of Mac OS X
http://www.symantec.com/docs/TECH131045
Removing Symantec programs for Macintosh by using the RemoveSymantecMacFiles removal utility
http://www.symantec.com/docs/TECH103489
About Symantec Endpoint Protection 12.1 RU4 Definitions in LiveUpdate Administrator 2.x
http://www.symantec.com/docs/TECH211582
Known Issues -
Symantec Endpoint Protection 12.1 RU4's right-click context menu for the Security Log does not appear when using a stylus on Windows 8
http://www.symantec.com/docs/TECH211590
Launching the remote Java-based Symantec Endpoint Protection Manager Console takes significantly longer with version 12.1 RU4
http://www.symantec.com/docs/TECH211353
Unmanaged Symantec Endpoint Protection Mac clients exported from the Symantec Endpoint Protection Manager do not prompt for an administrator password when disabling Auto-Protect or Network Threat Protection
http://www.symantec.com/docs/TECH212023
NOTE: You could also search on the Symantec Knowledgebase as well -
http://www.symantec.com/business/support/index?page=content&key=54619&channel=TECHNICAL_SOLUTION
Hope that helps!!