Unreal Engine 5.6 has not upgraded the preferred MSVC version past 14.38, which was also the recommended version in UE 5.5. Versions 14.39 and 14.40 are still banned for various compilation issues. Unfortunately, some third party libraries that we’d like to integrate into our game (such as gRPC release 1.73.0) require a newer compiler version than 14.38, as when ran against 14.38, they fail due to some unresolved external symbols in the standard library, and the accepted solution online seems to be to upgrade compiler versions.
As such, I’d like to ask whether Epic has done any testing of any UE versions against MSVC versions 14.42 and 14.44 yet, and whether you’ve encountered any issues that would prevent licensees from upgrading to those compilers? Is there a more-likely-to-be-preferred-in-future version between 14.42 and 14.44?
Hey there,
I just spoke with the SME for UBT about this. We are still waiting on some compiler fixes for 14.44, with the prior versions having some issues (be it compiler errors on our code that required compiler fixes, or bad codegen). We won’t be bumping 5.6 unfortunately, so it’ll likely be 5.7 before we can bump it.
Julian
Hey there!
Sorry my messaging was a bit confusing there. We have observed compile errors in our testing (issue listed here). It’s also important to note that we cannot switch this on until clang 19 undefined behaviour issues are resolved, since MSVC 14.44 requires at least clang 19 (if used as the compiler). As you can see with the above referenced ticket it’s been resolved in a new version, and new testing has verified that it fixes the issue. We are now just waiting on the clang 19 issue.
Julian
Thanks Julian! Just to make sure I fully understand here, does this mean that you’ve encountered both (internal) compiler errors on Unreal and also bad codegen? I’ve not seen any ICEs so far when compiling our game with MSVC 14.44, but bad codegen is much harder for me to test for, so that’s the spookier side.