I have recently seen a reddit post about it. No one from staff replied, I can't find it anymore. Two resellers of Ledger hardware included information on their website that Ledger discontinued Blue model. As far as I know, Ledger does not accept pre-orders for that model. I'm not surprised, who needed such big screen, Bluetooth and even battery in device which can't work without a computer? Release of Trezor T might have forced Ledger to create something better. A lot of people love Ledger for huge amount of altcoins available in their wallet. I would rather have a stable app which works all the time or at least lets me change the node like Trezor do.
Well, last year they were saying that they would release new software by the end of the year. Now, it's Q2 2018, I wouldn't be surprised if there were delays. However, I have to admit that mobile application looks great.