What are your plans with the currently named product OCS delivery channel / relay?
Office Communication Server is history a long time ago, and the only thing I can see regarding Lync is a workaround on how to get Lync 2010 to work. We're already on Lync 2013 (installed on Windows Server 2012), and both of those make installation / setup impossible.
The workaround for Lync 2010 involves installing the OCS core components, and those aren't supported in Windows Server 2012.
I'd say that all of our customers now use Lync, and it's a disappointment for us that we can't deliver notifications on Lync - either because it's not supported (2013) or because we don't know if it'll work when they upgrade to 2013. As far as I've understood, the 2013 release contains better support for mobile devices and we expect those who haven't already done so to upgrade soon.