In April, Microsoft kicked off Phase 1 of the public preview for the coming client. Phase 1 supported meetings functionality. Phase 2, which is rolling out today, July 5, adds IM, Contacts, and Presence. Phase 3 will add calling/voice support on top of the functionality delivered in the first two previews.
The expected release to manufacturing (RTM) date for Skype for Business for Mac is some time in this calendar quarter (Q3 2016), last we heard. Originally, the team was saying "Summer", but as of today's post, the team is now saying "Fall".
Microsoft officials said they currently have more than 22,000 individuals with more than 7,000 organizations in the Skype for Business for Mac preview. As the team is at capacity, it's no longer accepting new participants. Those already in the preview will automatically get the new updates as they're available.
In addition to IM, Contacts, and Presence, the Skype for Business for Mac preview now supports peer-to-peer calling, group video calling, and conversation history, according to today's blog post.
For those wondering when we'll start hearing about a Universal Windows Platform version of Skype for Business, the answer is: Who knows? I asked about this a couple of months ago and was told the team had nothing to say yet about its plans on this front.