Skype for business (Office365) with pidgin-sipe

By using the pidgin-sipe plugin for pidgin, it is possible to connect to Office365, Skype for business.

First off, add the sipe-collab PPA and install the two main packages:

sudo apt-add-repository ppa:sipe-collab
sudo apt update
sudo apt install pidgin pidgin-sipe

Start pidgin and add a new account.

Tab Basic:
Protocol: Office Communicator
Username: <E-mail address>
Login: <E-mail address>
Password: <Password>
Remember password: <Checked>
Local alias: <Your name>

Tab Advanced (anything not mentioned should be left with default value):
Connection type: Auto
User Agent: UCCAPI/15.0.4420.1017 OC/15.0.4420.1017
Authentication scheme: TLS-DSK

Credit goes to frytek on ubuntuforums.org. sipe-collab source-code can be found on github from tieto.