I was looking through the feature list and it looks like the lighting was primarily baked again?
yes SVOGI was axed, I think it was due to scalability issues.
Yes, the dynamic GI system is not available. Performance was an issue, you’d need a high end system so they took it out. They are still working on improving it and I think it will be added back in eventually once it’s performing better.
I haven’t really been actively keeping up with the newer engines since it was kind of pointless without knowing when they would drop. If you don’t mind one more question: Is lightmass any faster?
I don’t know if its faster but it has been improved a lot, also there is async light building so you can keep editing while you wait.
Is Enlighten integration part of the default UE4 editor like PhysX, or is it a separate plugin?
It’s not part. You can probably buy license for Enlighten and plug it. Integration hooks should be in.
Can I create a “realistic” day/night cycle without dynamic GI ? As in use directional lights to simulate the sun/moon and still get great looking shadows, etc. ?
Ah, well, that’s neat then.
Yes, you can. You’re limited on the number of shadow casting lights (more than a few and perf drops heavily), but you can definitely do day/night cycles with the UE4 lighting tech out of the box. We are doing it internally at epic for Fortnite, looks great.
Awesome, thanks !! any pointers/advice you can give ?
I’m a programmer so I won’t be of much use. If you have a specific implementation question, I’d ask it over at https://answers.unrealengine.com/ and someone who knows more can probably help out.
Great thanks. I’ll go take a look.
It was not axed, it was simply delayed. See this post from the rendering team lead on the old forums.
Keep reading his posts further down the thread for more information. It is for sure being worked on, but not ready for release.
In the meanwhile, we get to enjoy the thousands of other improvements made. 
I asked the question there, hope somebody has some advice. As you are a programmer do you know of any C++ tweaks I/we can do to implement something similar Engine side ?
I mean you have full c++ source access, so you can implement it yourself if you want.
The new Lightmass is a lot faster and cleaner than how it is in UDK. It isn’t the only way though, since you can go fully dynamic as well if your target platform can handle it.
I would like to only develop for Mid - High spec PC , so I’m sure my target platform can handle full dynamic. Can you please point me in the right direction I would need to focus on to start to implement fully dynamic if it’s possible ?
EDIT:
I was able to find a temp implementation of Dynamic GI here for all who want’s it : How to enable Light Propagation Volumes GI [ WIP AND BETA] - Rendering - Epic Developer Community Forums