If you where looking for long time support you already made a mistake because that was the Mx8.6 version. That one just have been updated wit 8.6.6. I would seperate the Atlas upgrade path from the Mx upgrade path. For now I would check if the newer Mx8 versions give me advantages and upgrade to those or otherwise stay on Mx8.7. For Atlas a bit of the same. If you see advantage then update your Atlas.
Thanks for your response. I’ll take that into account.