If you are currently running 2.1, the automatic upgrade check will now allow you to upgrade to 2.1.12 within your control panel. Once you are running the latest 2.1 release, it will report that an upgrade to 2.2 is available. If you would like to upgrade to 2.1.12 and the control panel reports that 2.2.0 is available, you may manually check for upgrades via Tools > Check for upgrades.