Hello,
Here is the List of SEP along with its Versions.
Symantec Endpoint Protection 11.0.780.1109/11.0.776.942 (RTM), 11.0.1000.1375 (MR1), 11.0.1006 (MR1 MP1), 11.0.2000.1567 (MR2), 11.0.2010.25 (MR2 MP1), 11.0.2020.56 (MR2 MP2), 11.0.3001.2224 (MR3), 11.0.4000.2295 (MR4), 11.0.4010.19 (MR4 MP1), 11.0.4014.26 (MR4 MP1a), 11.0.4202.75 (MR4 MP2), 11.0.5002.333 (RU5), 11.0.6000.550 (RU6), 11.0.6005.562 (RU6a), 11.0.6100.645 (RU6MP1), and 11.0.6200.754 (RU6 MP2), 11.0.6300.803 (RU6 MP3)
Now, Since you are carrying Older version 11.0.4202.75
We recommend you to upgrade the Symantec Endpoint Protection Manager and all clients to Latest version.
You can download the latest software from Fileconnect.
https://fileconnect.symantec.com/
Since you are carrying older version than 11.0.6005 (RU6a), there would be 2 upgrades you will have to go through. Please check the steps below:
1) From Symantec Endpoint Protection 11.0.4202 to Symantec Endpoint Protection 11.0.6005 (RU6a)
http://www.symantec.com/business/support/index?page=content&id=TECH131653&locale=en_US
2) From Symantec Endpoint Protection 11.0.6005 (RU6a) to Symantec Endpoint Protection 11.0.6300 (RU6 MP3)
http://www.symantec.com/business/support/index?page=content&id=TECH155655
Reason for Migration:---> check the Symantec Article below:
Release notes for Symantec Endpoint Protection 11.0.x and Symantec Network Access Control 11.0.x
About Maintaining Consistency of Software Versions throughout a SEP 11 Organization
http://www.symantec.com/business/support/index?page=content&id=TECH131660
There are no Known issues which are seen immediately, however there may be some issues seen after sometime.
This Migration is not a New install which requires uninstallation of older software. In other words, incase if you are carrying an older version of Symantec Endpoint Protection, you may not have to uninstall anything, its a Installation over the older version.
Advice: This is a Simple Migration.