With Rails 3.2 reaching EOL, it's time for Metasploit to upgrade Rails 4. This week's update only includes the Rails 4 upgrade and does not include any new functionality, bug fixes, or modules.
Upgrading after December 23, 2014
If you did not update to Metasploit 4.11.0 prior to December 23, 2014, you will need to read this handy blog from Eray Yilmaz to learn how to successfully update your Metasploit instance: HOTFIX: Metasploit Startup Issues After Upgrading to 4.11.0 (Update 2014122301). The standard method that you use to update Metasploit will not work if you are updating after December 23, so it is critical that you update Metasploit using the steps outlined in the blog.
How to Upgrade
To upgrade Metasploit Pro, go to the Administration menu and select the Software Updates option. To see how to upgrade your Metasploit installation, view this video.
PRO 4.11.2 updates to 4.11.3-2015061001
MSF3 4.11.2 updates to 4.11.3-2015061001