Downloaded new iOS for my 3GS and apps quit working

Apple iPhone - Downloaded new iOS for my 3GS and apps quit working

Is there a specific way to address this problem. Should they be deleted from iPhone before installing new iOS and then reinstalled.

Need some help as this is driving me crazy as some are paid apps.

iPhone iOS
When you install the new iOS it will wipe the iPhone, so make sure you back up all your data. That includes copying your photos and other things to your computer that iTunes does not backup or sync.

After the new iOS is installed then power cycle the iPhone. Then sync it. The apps should work.

That they don't work with the new iOS is rare, but it is on the developers end. The ones that don't have not been updated by the developer. Contact the developer for information on how to get them to work again or when they will be updated.