ok, the move was working better than expected
I have now a unity version which is from the outside an almost 1:1 copy to the last release version.
Now I ve to do some fine tuning and a few minor adjustments to the new engine before it's going back to upgrade more characters.
As of now I'm currently upgrading Cas, Vivian and Faron. Once this is done I'll put out a new release.
It won't have a new chapter but it should be a quite remastered version of the current release. 
And with most characters upgraded it will be much more efficient working on future chapters without the need to go back so often and rerender all again and again.
I ll make an update once I know more on the possible release date, but I guess early December