4.24-p4
Changes to the way UBT detects compiler version are going to trip people up. If a specific MSVC compiler version is specified in the BuildConfiguration.xml, UBT will now complain about it being missing unless it matches precisely the version number inside the actual cl.exe file. Previously it was more lenient regarding the build number.
As an example, my installation at \VC\Tools\MSVC\14.23.28105\ worked fine with ‘14.23.28105’ specified as the version in 4.23. In 4.24, it fails because the build number inside cl.exe (at the above location) is in fact 28107.