It's the replacement of the limitations placard (cockpit overhead panel) to reflect the 28,000lb approved maximum weight of a -800 aircraft.
It incorporates 253169A increasing the zero fuel weight from 17520lb to 18000lb to permit the GW increase.
I'm mainly an XP or later guy but if you have further questions on it let me know, I might have some older literature that could shead better light on it.
Last edited by HS125; 30th Mar 2015 at 03:32.