M26 OpenCPU availability

I want to select a 2G gsm module that supports OpenCPU and be cost-efficient. I have no certification concerns.
so far, I think M26 would be my choice.
now I have some questions:

1-where can I find documents for M26FB or M26FA as an original resource?
2- is it correct that only M26FA supports OpenCPU? (I infer based on Quectel_M66_R2.0&M66_R1.0_Differences_Introduction_V1.0)
3-does M26FA still produce? (since I found docs that is for 2014, and M26 doesn’t available on the main website)

I would be glad if someone answer mine.