TUI Seat Plan
 

I've flown with TUI (Thomson) on quite a few occasions be it the 787/757 or 737, I know that the 757's are being retired but I booked a holiday out of Bristol for Jan 2020 & when I pull up the the seat plan for the booking it just seemed a little odd, when I flew out on one of the 737's back in December the extra legroom seats were row 3/4/5 D/E & F with the extra space seats (emergency exits) in row 15 & 16.

The seating plan I've now pulled up for 2020 is identical to the 737 I flew in back in December, but this one is still rows 1 to 32 but has additional extra legroom seats in rows 17 & 18 A through to F as well as the previous configuration.
Any ideas what model plane this is, possibly a 737 Max ?