[douche]

The Skype for Business client is still essentially the same as when it was Lync 2013. In the early days of the rebranding, the version number had only jumped a couple dozen revision numbers, keeping the same major and minor versions, and still calling itself Lync 2013 on the about dialog. Changes on the server-side have been even less drastic.

Consumer Skype is still an entirely separate code base. The two IM platforms don't even speak the same protocol, and just barely interoperate.

The naming change is illogical as all hell, but Microsoft bought Skype, and suddenly Lync needed to be rebranded under the Skype umbrella. Before it was Lync, it was Office Communicator, before that Live Communicator, and before that, I believe went under an MSN name. It's always been hitched to the latest marketing bandwagon.

Lync/S4B is, sadly, one of the better enterprise IM systems, in comparison to other big players in that space, like Sametime, Jabber or Hipchat. It's still hot garbage.