+1
A version for 4.27 would be important, as there are many issues with UE5 and VR/MR that will only be fixed in 5.3, so we’ll have to use 4.27 for the foreseeable future.
Best
Andreas
Just so I’m following, is this something that is fixed but will need to be updated in the next version of Cesium for UE?
Yes, it will be in the next release, which will be early June.
Is it possible to get the update for 4.27 ?
No, we are no longer releasing new versions for UE 4.x. Epic doesn’t allow us to publish the plugin to the Marketplace for any versions other than the most recent 3.
A version for 4.27 would be important, as there are many issues with UE5 and VR/MR that will only be fixed in 5.3, so we’ll have to use 4.27 for the foreseeable future.
I’m really surprised to hear that. Like what?
If you really need to use UE 4.27, you’ll need to backport the fix to the old version of the plugin in the ue4-main branch and build it yourself.
Okay I understand, So basicly if I take the UE5 version that you’ll update and then compile it with UE4.27 it should work ? Or should I expect errors when compiling ?
No, the UE5 version of Cesium for Unreal will definitely not compile on UE 4.27.
You need to start with the ue4-main branch, as I said above, which currently compiles and works on UE 4.27, but is missing all the latest changes. Make sure you can compile from source successfully yourself before moving on to the next step (check the developer setup instructions in the Documentation directory).
Then, git cherry-pick the commits that you need into that branch. Fix any merge conflicts. Fix any compiler errors. Fix any runtime errors.
The fix for this issue has been merged to main in cesium-native. It’ll be included in the next release.
If you want to incorporate this change without worrying about other differences between the UE4 / UE5 branches, you still have to clone from ue4-main, but it should be simpler. The idea is to update cesium-native to the latest commit, then follow the rest of the the developer setup instructions to build the plugin.
Looking at the changelog, there were no breaking changes to cesium-native after April 2023, which is when we released the final updates to 4.27. So hopefully just updating cesium-native will work 
1 Like
Hi @Kevin_Ring, hi @kuyrem1,
No, we are no longer releasing new versions for UE 4.x. Epic doesn’t allow us to publish the plugin to the Marketplace for any versions other than the most recent 3.
That’s a shame, but if you can make the time I guess CESIUM might still be able to create UE 4.27 plugins and make them available on GitHub, this would be perfectly fine, the Marketplace is convenient but not needed.
And there are issues with UE5.x for VR/MR (e.g. bad rendering of clouds and horizon on Varjo’s high-end-mixed-reality headsets like the XR-3) that make UE5 unusable for serious simulation like our Lilium flight simulator. And sadly these issues will be fixed earliest for UE 5.3, the fixes didn’t make it into UE 5.2. And there are some performance issues for VR/MR, too - I talked to some UE devs from Epic about this, they are aware, it just will take them more time to fix everything.
So yes, it might be possible for us to create our own 4.27 plugins updated with newer cesium-native versions, but I expect this might cause some problems, maybe not right now but likely in the future. So releasing 4.27-plugins for the community via GitHub would be greatly appreciated, at least till UE5.3 arrives (I totally understand that you don’t want to support 4.27 endlessly, but it’s still a very important release widely used).
Best
Andreas
Sorry, but we’re unlikely to continue to support anything but the three latest versions of UE, absent a contract that obligates us to support older versions. The burden of all of those UE versions is just too high for a product we’re giving away for free. There’s no reason someone from the community can’t take on that maintenance burden themselves, though, if they’re so inclined.
As for VR/MR issues in UE 5.2, do you have links to Unreal Engine issues or other word from Epic about it? Our contacts at Epic have been pretty clear that people doing active development should be on 5.x by now.