If you're a GNU/Linux user, then you'll be very aware at just how horrible Skype is on the platform. Not only has it not been updated since June 2014, but the Skype team at Microsoft - perhaps when they were bored - added extra hoops and complications as time went on.
The craftier Linux users affected by Skype disabling group calls a few months ago simply changed their browser's UA string to"Windows/Edge" to get around the block on Skype for Web and were able to make voice calls to their heart's content.
Today, that appears to have changed, slightly, as the Skype for Web team decided to update the Skype for Web client to allow GNU/Linux and Chromebook users to make voice calls on the web client.
The silent and as-yet unannounced update has removed the browser UA string check that was previously only allowing Microsoft Edge browser to initiate calls, and they appear to have stopped using proprietary plugins for voice calls.
It's unclear if this was an intentional act by the Skype for Web team or if there has been a bug somewhere, but Microsoft hasn't spoken about the update as of yet.
Source PC World