Unless this accident is quickly proven to be the result of a different cause then the recent Lion Air disaster then its likely to result in a grounding of the type until the defect is fixed. If the cause is the MCAS again then a software update isn’t going to be enough, it’s back to the drawing board and no certification authority is going to allow it back into the air until the rectification is conclusively proven to restore safety.
Airlines are likely to ground their aircraft anyway before being directed by Boeing or their local CAA.