iOS 8.4 App Store updates issue

Turn your device off and back on. If this doesn't help, sign out from your account and sign back in.

Also, you can try resetting your settings.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

Alternatively, you may go to Settings - General - Reset - Reset All Settings

https://support.apple.com/en-us/HT201559

Same issue here, not only on my phone but also on two Ipads!

Resetting settings using the aforementioned instructions won't delete your data. However, you can backup your device first. Just to be on the safe side.

I was able to solve it half-way. I updated the apps in ITunes on my PC and then synced my phone with ITunes. Certainly, this can't be the ultimate solution.

Glad this helped you. You are welcome!