Originally Posted by
MSPeconomist
Currently MR legacy LTP is 2,000,000 lifetime points and 750 nights, valid through the end of 2018, which would get you LTPP in the new program. Otherwise, LTP in the new program is 10 Plat years and 600 nights.
Just to clarify for the OP, it's 10 years of NEW Platinum, meaning that any years you achieved Gold in the old Marriott program (50 nights) count toward the 10 years of Plat.
I suspect the OP is in a similar situation to me. I'm LT Gold in the new program and need about 33 more nights to reach LT Plat. I was consistently Gold in the old Marriott program.