Nope. That is not operational yet nor is there any word yet on when it will be implemented. Not sure where you saw August 1.
You have three years from the deadline to file an amended return. You can mail it now or wait for the e-filing option later--we do not know when that will be.
My professional program says the IRS has not sent out any efiling code instructions yet so the programmers have nothing to program yet and once they are issued the programmers will need to construct, test the system and be approved by the feds before it can go live ... this will not happen overnight and no date has been mentioned yet. I would mail in the amended return since this may not be operational for a DIY program this year.