I have personally updated to iTunes 10.5 and had no problem synching .ipas as with iTunes 10.4.x.
However, note that as of now there’s no definitive word from the jailbreak devs about how iTunes 10.5 may work with future jailbreaks. Several other blogs are reporting that it seems safe, but still to wait. This is a typical statement:
If you’re going to be updating to iOS 5 tomorrow, update to iTunes 10.5 today. (Jailbreakers, we don’t expect any trouble but air on the side of caution and let others test the waters first.)
In other news, for those who feared that an untethered jailbreak for iOS 5 was not possible, there may still be hope. This is whatiOn1c had to say on twitter:
As far as I know iOS 5 untether is covered by other people already. Guess who :p
