These are the current Zwift and Zwift Companion App versions:
Newest Zwift versions
This page updates automatically when a new version is released by Zwift. The information is also always available at the front page of ZwiftHacks.
Google Play Store links
For the Android Companion App the latest release date and not the version is shown. If you do not see this version/release date when you visit the app page in Google Play Store it is most likely because the latest version is not supported for the version of Android on your device.
Companion App: https://apps.apple.com/us/app/zwift-companion/id934083691