Mine stopped updating last night, as well. I also am experiencing crashes to the Start screen with Mail, and other weird problems (not being able to delete call history in the Phone app, for instance) after everything working flawlessly since launch day. I haven't found a solution, so I'm going to try a hard reset. I was hoping not to have to do that because it takes FOREVER to set my phone back up the way I want, but I can't think of anything else to try!