Hmm. I still don’t get it (maybe as I’m not a native English speaker). Is it possible to upgrade directly from EXE version 2.5.3.5637 to latest MSI 3.3.5? Or do I have to do another upgrade step in between?
Btw: we install updates via our software deployment (so we don’t use the Nextcloud integrated updater)
Thx
I understand that with the MSI a direct upgrade should work, but the integrated updater most likely does intermediate steps to 3.0.3 → 3.1.1 → 3.3.5. So if you want to roll out the new version via an automated software deployement system, you should be able to roll out the latest MSI directly. But either way, you would have to test the procedere on a few clients or in a test environment, before you roll it out in large scale. Just like you hopefully do with any other software… 
I verified: in our case the Nextcloud integrated updater does the following steps:
EXE v2.5.3 > EXE 3.1.3 > MSI 3.3.5.
But I’m still wondering why the developers do it like that and even more, why you shouldn’t need this intermediate step (= EXE 3.1.3) when upgrading from EXE v2.5.3 to MSI 3.3.5.
That I don’t know. But does it really matter, when you don’t use the integrated update mechanism anyway? I would spend my time testing if a direct upgrade from 2.5.3 to 3.5.5 with the MSI does actually work. Because if that works, then it should also be possible to roll it out via SCCM or another software distribution system, without the intermediate steps. → Problem solved → 
Yea, but I’m new to this Nextcloud stuff and I cannot judge if the missing intermediate step will cause other problems in future. That’s what I’m afraid of
A test upgrade from 2.5.3 (ExE) to 3.3.5 (MSI) works - at least there are no errors showing up. Maybe someone can confirm that we go this way in the next days. Otherwise I have to use your suggested trial & error method