Thanks for all your replies.
I thought it couldn't be that worse and with every new day there surely will be less bugs left.
But if the actual status is still a mess... you convinced me.

I'll try the 4.2.2 version.
And regarding to my question, I can prepare the 4.2.2 with all the subpages, add-ons, etc. on my webserver
and then import the user, posts, etc. data from my 3.8.5 Version with ImpEx.
Is that correct?