You can read about the highlights on the discourse blog:
The Linked account control feature looks good for controlling how you access your account.
You can now easily see, add, and revoke any available social logins directly from your account page
As well as Printed Backup Two Factor Authentication Codes. You have been able to enable 2FA, from your user preferences, since v2.0 but now with backup codes you can more easily recover in case of disaster!
etc! 
Oh, and something I also added as part of this upgrade is the ability to share a post via LinkedIn.
Just down the bottom there is the 
icon. Hit that to open up the share options and you will see there is now one for LinkedIn!
Hey… give it a go and share this topic!