Apple’s malware thwarting Gatekeeper launched more than two years ago, coinciding with the release of OS X Mountain Lion. Gatekeeper gives users control over what kinds of apps are installed on a computer, with the default allowing only Mac App Store apps from identified developers.

While a user can easily choose to disable the setting, the default is the best way to protect against malware since Apple reviews each app before it’s accepted into the store, and can remove any problematic apps. The developer ID is equally important because it allows Gatekeeper to block apps created by unscrupulous developers and determine if an app has been tampered with since being signed.

But, with Mavericks and Yosemite come changes that will require some developers to re-sign their applications and submit updates to the Mac App Store, according to Mike Beasley at 9to5mac.com. “Any apps built and signed on a version of OS X older than 10.9 will now be flagged by Gatekeeper as not having a valid signature,” reports Beasley.

According to a screenshot from 9to5mac.com, apps with signatures from OS 10.8 or older “will no longer be recognized by Gatekeeper and are considered obsolete.” To avoid this, developers are urged to update to Mavericks, re-sign, and re-submit apps built on older versions of OS X. Users will then be able to access apps at their full functionality – even if they themselves use an older version of OS X.

This update to Gatekeeper helps provide a safe environment for users to download apps in a curated setting that has proven most effective at eliminating malware.

Image: Cristiano Betta