IJ generally supports the latest stable AGP release at the time of feature freeze for a release — the current flow is that we need to take the AS code, extract their AGP support, rebase and patch it to work on the newer IJ platform (AS has historically been based on older IJ platform versions than the latest, as they have the reverse problem). I think IJ 2020.3 should support AGP 4.1, if not it may be they didn’t have enough time from when it went stable to when the IJ build was feature-frozen. It should be supported in the next minor upgrade, in that case, I think (but have no insider knowledge on that)