Launching Zwift app today says an update in required within 1 day. Since I didn’t want to risk an “update now” message just before tomorrow’s tour of london, I went ahead. That was hours ago, multiple phone reboots and download restarts. And it is still blocked. Other app updates are successful. Zwift simply spins for a really long time (an hour?!) then stops with the square in circle and never loads. Is there an error log somewhere I can check?
What version iOS are you running on your phone? You might need to update that as well since some app updates include changes that are a result of iOS updates. That is, Apple changed something that would have broken Zwift and/or was less than ideal, so Zwift changed something accordingly. As a result, new Zwift doesn’t work with sufficiently old iOS versions.
If that is not an option or does not work, then I recommend you delete the app and then download it again.
The latest version of Zwift for iOS is 1.0.43784 and was released 12 Dec, 2019.
iOS updating is not flawless. The Zwift iOS app is large.
Here are a couple of articles to add to Lin’s recommendation:
If the Zwift app is the latest version, the problem may originate from iOS. This app may only be applicable to the newer iOS version. Updating iOS may help to fix app crashes or unable to complete the installation. RecoveryTool Fix Recovery provides professional repair solutions for iOS system failures.