This page by David Papkin contains technical info about Skype for Business 2015
Client comparison tables for Skype for Business Server 2015
What’s new in Skype for Business Server 2015
Skype for Business Server 2015 resources
Configure the client experience with Skype for Business
Lync is now Skype for Business — see what’s new
Skype for Business Server 2015 Deployment – Part 1
Manage Registrar configuration settings in Skype for Business Server 2015
Skype for Business Planning Tool
Links for error conditions
Warning all persistent chat servers are down
Lync front end service not starting
est-CSExStorageConnectivity returning error code=50043
Skype for Business is removed when you upgrade to Office 2016
Integrated Exchange Archiving not working
How to Fix a Failed Database Content Index for Exchange Server 2013
Office 365 /SFB Online
Network planning and performance tuning for Office 365
PSTN Conferencing availability
Patch or update Front End Servers in Skype for Business Server 2015
Manage Centralized Logging Service configuration settings in Skype for Business Server 2015
Capacity planning for Persistent Chat Server in Skype for Business Server 2015