Opening mscz4 attachments in mscz3

Hello everybody,

A friend of mine and I are sharing musescore files on a regularly base sending our files by mail.
We work both in Musescore 4 now, but apparently mine (and others) mscz4 files open automatically as Musescore 3 on her device which of course is not possible. We removed Musescore 3 from her device, but even then it still want use 3 to open attachments instead of 4. How can we change that? I have no problems with receiving and opening mscz4 files as mscz4, so we wonder if we should change something in the settings.

Tia for answering us!