There is a ROLL *virtual* interim meeting in 45min, in case you didn't know:
https://datatracker.ietf.org/doc/agenda-interim-2019-roll-01-roll-01/ https://mailarchive.ietf.org/arch/msg/roll/7ZTSFLiVZEGYTHjL4yCm--j6mVI
A key discussion in this meeting has to do with building networks (LLNs) where the capabilities of the nodes varies. It would be great to have some RIOT-OS people join. It's entirely online, no sign-up, no fees, etc.