I started a conversion process to remove the NIB files from my iPhone app, to pass the whole interface to an only-programmatically version.
I noticed that when testing the app with my iPhone connected to Xcode, the old NIBs were still in use (a strange mix of the old and new interface appaired on screen), until I didn’t deleted the app from the device and I reinstalled the app from scratch.
I was asking to myself if my existing users will be affected by this problem, when I’ll upload this new version on the App Store.
Existing users will not be affected by this problem.
I’ve noticed this problem before too and I believe it could have something to do with how iOS caches the contents of the NIB after loading.