Today, Exchange Team also released new rollup update for Microsoft Exchange 2010 SP3
After installtion of Rollup 5 for Exchange 2010 SP3 your Exchange version number will be raised to 18.104.22.168
Rollup 5 for Exchange 2010 SP3 can be downloaded here:
Update Rollup 5 For Exchange 2010 SP3 (KB2917508)
And description of new rollup you can find here:
Description of Update Rollup 5 for Exchange Server 2010 Service Pack 3
As always we recommend to test this rollup in a test environment first.