Apple released together with the new version of OS X Yosemite 10.10.2 a security update for those users who are still on OS X 10.8 Mountain Lion and OS X 10.9 Mavericks. This update is for security purposes and is used to fix some security problems related to Bluetooth connections, Spotlight and access to the Mac App Store.
The version released is the Security Update 2015-001 and it is available to all those users who, for whatever reason, are still in versions prior to Yosemite. Apple does not stop solving security problems and errors that are found in these versions prior to the current OS X Yosemite, proof of this is this update.
In addition to solving these security flaws, the new update adds a new version of Safari for both systems, in the case of Mountain Lion is 6.2.3 and for Mavericks 7.1.3. These versions correct problems related to WebKit and improve the security and reliability of the browser.
Obviously what we recommend from Soy de Mac es update our machine asap, so if you did not update today you can access directly from the Mac App Store by clicking on the Updates tab or from the apple menu - App Store ...