Find “Date & Time” and turn ‘Set Automatically’ to OFF
Toggle the date to sometime in the distant future, months ahead
Tap back to the “General” section and wait a moment
Relaunch the App Store and go to “Updates” – usually nothing will appear right now
Now go back to “Settings” and back to “General” and “Date & Time”, flipping ‘Set Automatically’ back to the ON position to get back to the real date and time in iOS
Exit out of Settings and return to the App Store app, then back to “Updates” – you should see the proper updates available now