I got the 1.7.8 fw installed duringe wipeing- /factory reset option on Tolino.
That version had some problems with the German Onleihe, because (some) publishers changed something in the ePub. We don't know what, because due to the DRM we can't look.
nor does the 10.0.1 fw. (that's why I dont think it is a firmware thing, rather some Adobe routine change, that the Tolino is not ready for).
10.x works for most German users, at least with the German system.
There are probably differences, but I think (sheer guesswork), that your libraries use the latest Adobe Content Server, too. AFAIK there haven't been any changes this year in the server software.
@divibib-support, can you confirm that?
I coud off course try to also install the 1.9.4 firmware, but where do I find that version?