Is there a successor project to Omega 4? I'm a big fan of the Omega base theme, trying to make sense of what's going on with that project. 

What I'm trying to do, is work with something similar to Omega 4 that is actively maintained on both 7 and 8 and will be capable of being upgraded to Drupal 8 in future.

I've read that there was a public falling out among the maintainers and that Omega 5 is progressing in a very different direction with different aims to Omega 4. I've also read that the Omega 4 maintainers are giving it minimal maintainence with many hints that their efforts will be focussed on other projects under other namespaces, and there have been no new dev releases since July 2015:


  Omega 4.x is still minimally maintained (I am committing bug-fixes and other critical / major patches). However, I am not interested in further moving on with anything under this namespace as stated previously in other issues. The reasons for that are well known and have been publicly discussed... There won't be any extended effort from me (and probably not from Matt either) to expand on the existing functionality of 4.x or even work on a new version... I will keep maintaining the 4.x version of course though so you can totally feel safe when using that at least.


Is there a new project that continues what Omega 4 was trying to achieve under a new namespace, that will be actively maintained on Drupal 7 and 8?



I've seen Khan described as "the omega 4.x successor for drupal 8", but it's had no work since 2014 and its project page is... baffling. It looks more like a Drupal community in-joke than a serious project. There's a thread with many people asking about this, but no clear answers.
I found what looks like an explanation from 2016. It looks like Omega 4 is not going anywhere.


  ...both new Omega versions (7.x-5.x, 8.x-5.x) probably have nothing in common with (7.x-4.x) and are not the successor of Omega 4.
  
  The successor to (7.x-4.x) is new project Khan so all the questions about that should be posted there. Truth to be told, there is not much activity there, since.
  
  So if you wish to make some sort of continuation of current 4.4 code base to D8, probably you will have to do it yourself. Personally, I do not think it will make much sense as the differences between D7 and D8 would not leave much in common.


The same user asked what the status of Khan is two months ago and hasn't received any reply. In another thread, the maintainer posted that Khan is postponed indefinitely:


  ...This is a serious project but since I am currently focusing on GraphQL for Drupal you can consider it postponed until I am done with the first release of that module.


So it seem fair to conclude that there is no Drupal 8 successor to Omega 4 at time of writing. 



Life is too short for drama, so I personally am going to (reluctantly) drop Omega and switch over to Bootstrap.