The Altiude 32 can be bought in:

08-channels
16-channels
24-channels
32-channels

And if you buy the lower channels models you can uppgrade to more channels for the same cost as the price difference between the different models.
So it will not cost more to buy the 8-channel model and later upgrade to the 16-channel model than to buy the 16-channel.

The new Altitude 16 will be 16-channel only and can not be upgraded to any more channels than 16.
And as far as i know the Altitude 16 will NOT have any digital out, only analog XLR.