Flashing of s7 edge

Hi guys,

I really wanted your opinions before I do something. I have a s7 edge SM-G935FD bought from the UAE. Since i reside in india i wanted volte support which currently my phone doesn't support.
So I came across flashing via Odin and getting an Indian rom from sammobile.
I haven't done it yet, but was in confusion of the authenticity of the rom whether if it is official and since Oreo is round the corner would I be getting the OTA update if i flash it.

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