When is the Lightroom 6 beta released?

Adobe never said such things. It was all people making fake rumors to draw attention. At this point, nobody knows (even if they do, they won't tell). It could be today or next month or next year.

Rumors have pegged March 9th, 2015 as the expected release date and it seems legit this time - The box image, new features and specs have already been leaked out. It doesn't look like there will be a pubic beta this time around (no sign of anything in Adobe Labs).

Rumours of March this year have been floating around since last December - and they're still just rumours.

Probably best if you didn't encourage people to put store in unfounded rumours on here.

Ever since LR Mobile was added to LR, there have been no public betas and no release candidates like in the past.  I think the LR team is just more busy than ever and can't afford the delay that a beta or release-candidate cycle adds.  Of course that means some issues will likely be missed. 

they released a beta, just not publicly, and likely won't release it publicly