To Manually Update Apps (ie. ResponsiBlue or Zoom) on an iOS Device:
Open the App Store on your iOS device.
Tap your profile icon at the top right of the screen.
Scroll down to see available updates and release notes.
To update a single app, tap Update next to the app you would like to update (ie. ResponsiBlue).
OR
If you would like to Update All the apps that need to be updated, tap Update All. This will queue up all the apps that need to be updated. This may take some time depending on how many apps need updating.
To Turn on Automatic App Updates on an iOS Device:
Go to Settings on your iOS device.
Tap App Store.
Under Automatic Downloads toggle on, App Updates.
Reference:
https://support.apple.com/en-us/HT202180