CRM 2011 Update Rollup 4 and Update Rollup 5 cannot be uninstalled

In case you miss the small print that accompany both Update Rollup 4 and Update Rollup 5 you should note that neither of these updates can be uninstalled due to the significant changes they make to the database. So you definitely want to perform a database backup before installing and perform the necessary testing in a test environment before applying to production.

So what are the significant enhancements/improvements that prevent uninstalling? While Update Rollup 4 seemed to mainly focus on some performance improvements, Update Rollup 5 has a slew of improvements including:

• Chart Design Enhancements
• Dialog/Workflow Enhancements
• Enhanced Data Management
• CRM Outlook Client enhancements 

Not too shabby indeed.