On Wed, 2 Apr 2025 19:02:23 +0200
Raul Claro <raulclaro@???> wrote:

> Hello, I hope somebody can help me with this problem.
>
> I use Devuan Daedalus and I updated it yesterday.
>
> Now the *fonts* in the applications Libreoffice, Thunderbird, Caja
> (Mate), Firefox, *are tiny*. I can increase the size with the
> Display-Options but they keep going back to tiny all the time.
>
> What is wrong?

You have to increase the font size in the settings for each program
and/or display manager (X11, qt3, qt4, qt5, etc).
Also did you save and exit after you adjusted each font?
Some programs do not update settings/configuration until you do this.

Fonts are the bane of high resolution displays.