Hi, @ivenwang
I haven't heard of any development problems! The Block one team did previously mentioned being ahead of schedule and believed the mulithreaded engine would be ready by June which might still be the case. It does seem that the multithreaded public testnet might not be realeased so in that event it would be unwise to release it untested in that regard.
There has been some discussion on the changes, but it is still looking like everything is still on target.
I posted an update earlier that focuses on the changes
https://steemit.com/eos/@johnchamberlain/eos-multi-threaded-parallel-processing-execution
ok thanks