Connect to your Skype for Business Office 365 Account using Pidgin

Add the following PPA: https://launchpad.net/~sipe-collab/+archive/ubuntu/ppa (not needed for Ubuntu 18.04)
Install/Update pidgin and pidgin-sipe packages
Create a new account with type “Office Communicator”
User name should be user@domain.org
Leave the “login” empty
In the Advanced Tab, under server, enter sipdir.online.lync.com:443
Connection Type and Authentication Scheme should be set to Auto
Use the following as the User Agent: UCCAPI/15.0.4420.1017 OC/15.0.4420.1017
Enjoy!!

About Ahmed Tawfik