From what I can tell this timeline is suggesting that the retroactive raises are not going to come as soon as people would have hoped. In order to earn all of the money due to you a teacher would have to stay in the system until the last paycheck in 2020.
According to the Movement of Rank-and-file Education (MORE), a caucus within the United Federation of Teachers (UFT), this contract is not on par with what the other public sector unions received and - more problematic - does not even provide raises on par with inflation and cost-of-living increases. Meanwhile, the UFT is touting its success in negotiations and is happy to share the news that health care costs will remain stable but there will somehow be $1 billion in savings realized over the course of the new contract. I wonder how that will play out.
I have been hearing some teachers say they are interested in voting NO on this new contract, but that the elementary school teachers and the retirees might out-vote them. We will see what happens soon enough.