Requires upgrade but no upgrade available (Android)

I logged onto Zwift on my Android device this morning but was told that I needed to upgrade.

Usually, the app upgrades itself automatically before the homepage, but today it took me to the login screen and displayed a message for me to manually upgrade by clicking an Upgrade button.

On my device, it offered me two options to upgrade to the latest version:

Samsung store
Google Play store

On clicking each of these, no upgrade was available.

The Samsung store wouldn’t let me view the upgrade, and the Google Play store said I was running the latest version, with no upgrade available (it just offered Uninstall and Open as options).

So, I couldn’t ride using my main device; I had to use my iPhone which doesn’t really work well with my Chromecast and was glitchy.