SEP 10.0 and SEP 12.0 Virus pattern difference

Dear all,

We have two group of SEP.

Old PC XP install will SEP 10.0

Win 7 VDI is install with SEP 12.0.

We found that this week, the SEP 10.0 Virus pattern is kept on 2013/07/08 while the SEP 12.0 virus pattern date is on 2013/07/12.

Check with the System Log of SEP 10.0 Client, it run the live update every day.

When we manual run the live update in SEP 10.0, it said the symantec product is uptodate.

Why the virus pattern had so big difference between these two versions?

Please kindly help.

Ivan