There is a report that the follow-up to the Canon EOS M10 will be coming on July 20 alongside the EOS 6D Mark II and EOS Rebel SL2. Again, we cannot confirm this and this is the first time we've heard about the EOS M20.
The M10 was announced back in October of 2015, so a replacement is highly probable. We'd expect an incremental update to the latest image sensor and DIGIC 7.
More to come once we confirm it.