17.2 update old projects to flexbus?

When opening older projects created in Resolve 16, audio busing mode tab in Fairlight settings has 'Use fixed bus mapping' ticked and greyed out.

Does anyone know of a way to update them to flexbus?

Flexbus is so much better on 17.2 created projects. ADC now seems to be working well along with seamless mix drop-ins

The two Bussing architectures differ significantly preventing Fixed Bus Projects being updated to Flex Bus other than via a manual process.

For reference, this architectural difference also results in dedicated Console Presets folders being provided for Projects set to use Fixed Bus mode and Flexi Bus Projects - these presets aren't completely interchangeable between Bussing modes.