If I try to enter "Mein Unternehmen" the app shows an Altert ("Attention") with the following text:
"SubTotal encountered a non-recoverable error ('Only TrueType glyf fonts are supported.').
If the problem persist, please contact the developer. The app will now quit."
I can only click the button "OK" and than the App quits.
The behaviour is identical if I try to generate or show the pdf file of an existing bill.
The app quits instantly if I call "Rechnungsarten" and click on one item of the list.

The behaviour is new.
The font in use is Klinic Slab. It's format is OpenType (CFF).
Currently I see no way to change the font so that the alert will not show up.
SubTotal version: 1.8.4
OS + version: Tahoe 26.5.2 (25F84)
Device model: MacBook Pro 16", 2021