Hello,
The Latest LUA version is 2.3.2 and the installation file is included on the Symantec_Endpoint_Protection_12.1.2_Part2_Tools_EN DVD which can be downloaded from https://fileconnect.symantec.com/
Once you have downloaded the Symantec_Endpoint_Protection_12.1.2_Part2_Tools_EN, please unzip it and then go to -
...Tools\Liveupdate\LUAESD.exe
OR
To Grab a Copy of Liveupdate Administrator (LUA) version 2.3.2 Utility, create a Case with Symantec Technical Support and they would provide the same.
How to create a new case in MySymantec (formerly MySupport)
http://www.symantec.com/docs/TECH58873
Hope that helps!!