Hello Community, maybe especially Kai 
Could you tell me, or give me some literature, on how the architecture between openHAB 2 and openHAB 1 is distinguished? What are the main differences? I think about more than, there is the possibility of auto discovery and the new Paper UI
Why didn’t all oH1 Bindings work with oH2?
I hope that this question is not to big?
Thanks for all answers.
That’s quite a big question - there’s a lot that’s changed… 
I’d suggest reading the ESH documentation first since OH2 is based on ESH.
In general openHAB 2 is an evolution of openHAB 1. The main technical difference for a start is that the namespace of all the core bundles has changed to org.eclipse.smarthome. Besides this, the architecture stayed as it was. The “evolution” is then mainly new features that come on top: Like the Things, Discovery, a much improved REST API with SSE, etc.
Well, in theory all of them should work and I can only see 3 persistence services being listed as incompatible here: https://github.com/openhab/openhab2/blob/master/docs/sources/addons.md#currently-incompatible-1x-add-ons.
For all bindings that are not yet listed as being compatible, I am asking you to test them!