According to Jethro's today, Jet2 have acquired a further 5 second hand B737-800's (G-DRTP, G-DRTR, G-DRTS, G-DRTT & G-DRTV), all ex Primera aircraft, due prior to summer 2019.
So 13 second hand and 1 new B737-800 still to join the fleet before summer 2019 now!!