It was reported not long ago that Sparrow had its most recent app update submission rejected by the App Store. It had nothing to do with getting around Apple’s laws on push notification. Instead, it was to do with the way it handles Rich Text editing. Just another example of Apple making sure that Google knew its garden walls were still there probably.
But, on a positive note: the update is here. Version 1.3.3 features some much nice improvements: iPhone 5 optimization and Passbook support. Download the app here. I’ve been looking around the app for a little while now, and haven’t been able to get it linked up with Passbook yet. I’ll keep you posted on my twitter feed if I have any joy with it.