I think Ableton started supporting the VST3 standard only in v11. However, the implementation was not perfect. Two main problems that made me rather not use VST3 in Ableton (despite the advantages of VST3, if properly implemented):

• VST3 plugins' presets are not available within Ableton, so any plugin without a dedicated preset management system (hello Plugin Alliance plugins and many others) will not show its presets

• When using an offline oversampling setting to prevent aliasing in the final mix (while keeping the realtime CPU drain low) Ableton will not apply the offline setting, since it fails to recognise the offline status of VST3 plugins in particular

Can any of the Live 12 users tell me whether these issues have been solved?

 

Following, as curious myself...