I had done a little bit of research on this subject before.
As far as I found, almost 75% of the old brokers use Odin. Only those who are newly set up offer other platforms.
But you need to exclude many of the big brokers like the banks, share khan, motilal, anandrathi, India Bulls, iifl.
Most of the other medium sized old brokers provide ODIN.
Please correct me if I am wrong