When the COP21 was signed, a lock was added binding the countries entering it for 4 years, counting from November 4, 2016.
Commitments from other countries push accord forward and is set to be activated on 4 November after the EU, Canada and India ratify the agreement
However, the ratification locks countries into the deal for four years, so an immediate US exit wouldn’t be possible.
The emphasis in the above quote is mine.
On June 1st, 2017, President Donald Trump announced the US would withdraw from it.
So whenever Trump will have all the paperwork done, will the US still bound by the agreement until November 2020, or has Trump actually found a way to "exit" it sooner?