Jetpack 2.9 is out! We’ve got a few exciting new additions — Multisite support, a Related Posts module, and a more secure Single Sign On — along with many smaller improvements and bug fixes.
Manage all your Multisite connections with one login
Logging in to each blog on a Multisite network to connect and configure Jetpack can be time consuming. Now, you can administer them all from one master account. When network-activating Jetpack, you’ll see a new Jetpack > Settings tab in your Network Admin. From here, you can manage all your blogs’ connections, control whether individual blog admins can reconnect with their own account, and designate which Jetpack modules are activated by default.
Make your site stickier with Related Content
The Related Posts module encourages your visitors to stick around longer by displaying links to additional content on your site related to what they’re currently viewing. Usually, analyzing website content to suggest relations eats up precious server resources. By utilizing the power of WordPress.com, the Related Posts module gives visitors more of what they came for while keeping your server resources freed up.

More security with Single Sign On
The Single Sign On module already gives you peace of mind against compromised user accounts because WordPress.com handles all the authentication for you — your site never touches the user’s private credentials. This release takes security a step further by giving site administrators the ability to require users to have Two-Step authentication enabled on their WordPress.com account before they can log in.