kIoChanged behavior?

For cases where I want to change the output configuration of my plugin, the VST faq recommends: componentHandler->restartComponent (kIoChanged);

It also states that Vst::IAudioProcessor::getBusArrangement / Vst::IAudioProcessor::setBusArrangements calls fill follow to finish setting up the new arrangement - this makes perfect sense.

However, when I make the restartComponent call, I don’t see any calls from the host to either of those methods (or, for that matter, getBusCount, getBusInfo, any other bus/arrangement related API’s). I’ve tested this in both Reaper and VST3PluginTestHost - am I totally mistaken about how restartComponent(kIoChanged) should be used, or am I somehow hitting bugs in both Reaper and Steinbergs test host?

The VST3PluginTestHost does not support this. And it looks like that Reaper also does not support this yet. They are often very quick in implementing VST3 stuff, just give them a hint in their forum.