I'm looking for a software with which I can plan appointments.
It should also be possible to automatically save this data on a USB stick.
It would also be good if the data could be synchronized, since I have 2 notebooks in use. One with Linux, one with Windows.
Thought of Lightning, but I'm not sure as there seem to be some issues with the versions.
Do you have an idea?
Try it with EssentialPim (free / pro).
https://www.essentialpim.com/de/
The program runs under Windows, but should also start under Linux with "Wine" and work with "certain restrictions".
https://www.essentialpim.com/blog-and-news/blog/how-i-run-essentialpim-under-linux
(Maybe you are a little more experienced with Linux than the author of this blog…)
An Android and iOs app is available free of charge.
You can first test the free version on both systems.
You can then estimate later whether you need the commercial Pro version or two of them. The functional difference is, however, quite large:
https://www.essentialpim.com/de/pc-version / pro-vs-free