Hello,
Supported Version information for Endpoint Protection for Windows XP Embedded 5.1
EOSL - End of Support Life on 10/15/2014
Keep in mind that the full SEP 12.1 is supported on XPE since SEP 11 MR2.
Final note: here is an enhancement request that you may be interested in voting for: https://www-secure.symantec.com/connect/ideas/increase-frequency-updates-sep-windows-xp-embedded
Check this Article:
Migrating the Symantec Enterprise Protection 5.1 Server to Symantec Endpoint Protection 11.0
http://www.symantec.com/docs/TECH92394
Symantec Endpoint Protection and Symantec Endpooint Protection for XP Embedded are 2 different products.
Check these -
http://www.symantec.com/endpoint-protection-for-windows-embedded
http://www.symantec.com/endpoint-protection
Incase, if you are carrying License for SYMC ENDPOINT PROTECTION FOR XP EMBEDDED 5.1and want to transfer to SYMC ENDPOINT PROTECTION 12.1, then I would request you to get in touch with Symantec Licensing Department.
You can contact Symantec Licensing Department for the same.
Website: http://symantec.custhelp.com
Phone number: 1-800-721-3934
Email: license@symantec.com
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Hope that helps!!