The available mqtt libraries for embedded devices have either memory leaks or cause memory fragmentation. On the other hand there are very mature, block-allocating http implementations.
Personally I do understand why they have gone with http. But some kind of real-time channel like websockets, server-send-events or something udp based would have helped.
Those are great news Zhan. Looking forward for more products from Sonoff with DIY for the ones that do not want to use the manufacturer cloud neither flash the devices. Please also include on the wish list a Basic R3 RF with dry contacts since that is key for many integrations and avoid unsolder the rele from the PCB.
I Cant wait to get Sonoff devices binding for Openhab. Flash Tasmota will be really waste of time if you have many devices. Not only R3, I hope binding with Sonoff Touch switch will be available soon.