Seattle Times reports (24 June) that Boeing may be restarting test flying as early as next Monday. Then providing the modified MCAS is accepted, the aircraft could return to service in Sept.
The initial inter-authority agreement would relate to MCAS, although Canada could include pulling SS cbs.
Full agreement on other system changes, consequences of AoA failure, is being debated, but likely to be a requirement for MAX -10, and retrofit to all variants by -10 certification date.
Possible areas being considered discussed here :-
Boeing 737 Max Recertification Testing - Finally.
https://www-seattletimes-com.cdn.amp...ontrols/?amp=1