Restore a canvas app to a previous version in PowerApps.
Restore an app from your account
* Open powerapps.com, and then click or tap Apps in the left navigation bar.
* Near the right edge, click or tap the info icon for the app that you want to restore.
* Click or tap the Versions tab, and then click or tap Restore for the version that you want to restore.
* In the confirmation dialog box, click or tap Restore.
A new version is added to your list.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/restore-an-app