You are running the upgrade over a remote ssh connection with a frontend that does not support this. Please try a text mode upgrade with 'do-release-upgrade'. The upgrade will abort now. Please try without ssh.
Rwyt ti'n rhedeg uwchraddiad dros gysylltiad ssh o bell drwy rhyngwyneb blaen sydd ddim yn cefnogi hyn. Tria uwchraddiad modd testun gyda 'do-release-upgrade'. Bydd yr uwchraddiad yn dod i ben nawr. Tria heb ssh.