Nextcloud 15nnnn

Hi, I just cloned my Nextcloud 14 VM to test an upgrade to Nextcloud 15. It seems Nextcloud 15 does not accept keeping my TOTP authenticator, but I want to enforce 2FA. What is the preferred replacement for Free TOTP? My preference is an official app that emails or texts a code instead of using TOTP (if I need to restore a backup, it appears TOTP is no longer synced). Any suggestions? Thanks!