Any timeframe for Sprint releasing a new BIS?

BIS 2.5 was just released. What version are you looking for?

2.5 - when did they release and how can you get it? When I log in it doesnt prompt me to upgrade.

You already have it. It's not something you need to upgrade.
It was a back-end upgrade that was handled for you.

Is there some functionality that you were expecting that perhaps you're not seeing?

Are you asking about BIS? Or device OS?

Sprint has already installed the latest BIS. You don't need to do anything. In general, it won't do anything for you, until...

OS 4.5 is released. Sprint has not said when they'll be releasing. Or, even if they are releasing. Presumably, they will.

So, until OS 4.5 is released, you don't need to do anything.