Hello there, yonatanzek.

It sounds like you are unable to update apps from the App Store since updating your iPhone to iOS 8.4.1.

The first thing I'd recommend is signing out of the iTunes Store and App Store from Settings by using the instructions found here:

Sign in with a different Apple ID on your iPhone, iPad, or iPod touch - Apple Support

iTunes, iBooks, and App Store

1. Tap Settings > iTunes & App Store.
2. Tap your Apple ID. If you see the option to Sign In, you can change your Apple ID now.
   
3. Tap Sign Out.

 

Once you've signed out, then Force close the Stores and Settings by using these steps:

Force an app to close in iOS - Apple Support

Force an app to close in iOS

If an app isn’t responding, you can force it to close.

If an app is unresponsive and your iPhone, iPad, or iPod touch still reacts to button presses, you can force the app to close:

1. Press the Home button two times quickly. You'll see small previews of your recently used apps.
2. Swipe left to find the app you want to close.
3. Swipe up on the app's preview to close it. 

   

After this is complete, then restart your iPhone:

Restart your iPhone, iPad, or iPod touch - Apple Support

Finally, after the phone has restarted, sign back into iTunes and App Stores and test the issue once more.

Thanks for being a part of Apple Support Communities.

Cheers,

Pedro.