Re: In upcoming window 10, Is OTG supports in lumia and window phones
Maybe not, for low end Lumia, or not at all. Maybe yes too, if microsoft has realized that they want to compete with other OS.
If you really need OTG, choose other OS that already support it.
Windowsphone/Windows still need maybe 2years more (slow development pace, fact!), to develop stable OS that can compete with others, and consumers finally can enjoy all general features that other OS can give right now, without software limitation, like equalizer only for Lumia Mid-end up.
Choose Windows if you really need it's feature available now. Don't bother waiting....its take long long time to wait a single usefull feature available on update (very slow development speed).