If you try to put the 1537 into this thing, the MCU will hit the Paddle board, and you'd have a gaping hole where the 3.5mm would be.
If you try to put a 1697 into this thing, which also has the 3.5mm port, the shielding of the RF board will hit the Paddle board.
Just from the looks, I can't imagine they changed the core of how it works, but I'd need one that I could tear more into to know for certain. The buttons are all still in a CG layout, and the Triggers are still Halls. I'd have to scope them to see if they changed anything there, but for all intensive purposes it's the same as a 1697. What I mainly meant by this one having different code is for the 4 Paddles and then the 1/2 selection switch. The 1697 is capable of being this 1698, but I doubt it has the connections broken out even if you could update the MCU on it.