Internet Box 3 keeps downgrading itself automatically

Hello,

Since some weeks firmware 14.20.30 is available for the Internet Box 3. This version is available both in the Swisscom website and directly from the router (a banner is shown in the overview page saying that an update is available).

I have updated the firmware some weeks ago and it worked without issues for many days. The new dark mode looks very nice. However, I noticed one day that the dark mode was gone and only later I realized that the router had downgraded itself to 14.10.30.

I updated again some days ago, and the same has happened once again.

What is going on? First, why is the router even able to downgrade? Shouldn’t there be a downgrade protection for security reasons like most firmware these days? And second, how can I disable this behavior? I don’t want to keep updating the router to find in the next day that it’s again running the older version.

Thanks!