I was able to just edit the uproject file in Notepad++ and change the EngineAssociation to “4.3”, upgraded without a hitch. Should look something like below:
{
"FileVersion": 3,
"Version": 0,
"VersionName": "0.0",
"EngineAssociation": "4.3",
"Modules": [
{
"Name": "MyProject",
"Type": "Runtime",
"LoadingPhase": "Default"
}
],
"EpicSampleNameHash": "0"
}
EDIT: I should clarify, my project is remarkably simple, with only the GameMode and Character classes overridden. YMMV on more complicated projects.