Today we've released UTM 9.704. The release will be rolled out in phases.
Yes It's right that changing Wifi or Reboot will cause again Problmes.
My SSID's are all Without Spaces.
Hope Sophos will Fix it soon.
I figured out the root cause of the WiFi issue. Sophos forgot to add quotation marks around the WiFi SSID check in line 24 of /usr/bin/wifi_pdog.sh, causing WiFi networks with spaces in their name to be errorneously marked as not enabled and consequently causing the script to restart the wifi interfaces every 2 minutes. Given that Mr. Dietrichs' solution is non-persistent (unfortunately so is manually adding the missing quotation marks yourself as these edits are not persistent between reboots), the hot-fix is to rename any WiFi networks with SSIDs that have spaces in them...
Check the comment from Jörg Dietrich. This workaround does indeed work.
I can confirm the wifi (AP55) issues after the update
Wifi not working any more after this firmware. We have more than 20 clients with problems.