The latest version of the Atlassian Plugin SDK is now available on the Atlassian Marketplace. So please feel free to update at your convenience.
You can find the release notes in Atlassian Marketplace.
APT-Get users please remember that after our recent changes to the way sdkrepo is hosted you will no longer be able to update using the apt-get tool. You should uninstall your Atlassian Plugin SDK using apt-get and then re-install the latest version using the instructions found in the documentation: Install the Atlassian SDK on a Linux or Mac system