Some users are reporting recently apparent problems updating iPhone and iPod Touch applications through iTunes, with the iTunes erroneously reporting that no updates are available.
According Apple Discussions poster mhoutman:
"since the last couple of days i have the following problem:the updating of some apps (shazam) was first visible on both my iphones, but the next day it disappeared. the same with itunes: it was not visible. today the same with touchgrind: visible on my iphones but not visible in itunes.
We are not sure where the problem lies, but we have witnessed the same problem on our iPhones and iTunes. The problem is not limited to the iTunes store in the US--users in Germany, Russia, and elsewhere are reporting the same issue.
Possible fix: Setup as a new phone Try setting your iPhone up as a new phone then redownloading an missing applications. To do this, perform a restore in iTunes, then choose "setup as a new phone."