Seems there is a new transient brightening very quickly in M31, listed in the TNS (Transient Name Server) as a PSN (possible Supernova). Designated AT 2020plo (see discovery certificate attached).
Discovered by ZTF,
https://www.ztf.caltech.edu/
Seems it was mag 20 or less on the 15th July and within 1 day was up to mag 15!
Stay tuned, if it is indeed a Supernova this could be big!
I have a quick screen grab from SkyX and the new transient position will be in the centre of the box.