iOS 8.4 Bug Fixes
Apple also includes a number of bug fixes in iOS 8.4. You may not see all these bugs, but if you are running into iOS 8.3 problems, you may find relief with the iOS 8.4 update.
One of the big iOS 8.4 bug fixes now allows GPS accessories to deliver location data to the iPhone and iPad. We did not run into any problems with GPS on iOS 8.3, but if you use these accessories, this is a must install update.
Another fix Apple calls out in iOS 8.4 is related to the Apple Watch. On iOS 8.3, Apple Watch apps would some times re-install. In iOS 8.4 this should not happen, so you can finally manage your Apple Watch apps easily.