For the first time, a major cyber attack successfully targeted Apple’s App Store. A number of Chinese developers accidentally used XCodeGhost, a counterfeit, malware-infected version of Apple’s Xcode app-building software. The program steals user information, and was embedded in hundreds of apps, mostly in China. Affected apps include Angry Birds 2 and the Tencent-developed WeChat, which has over 500 million users. (Find a larger list of affected apps posted at Business Insider, courtesy of security firm Palo Alto Networks). Tencent says that, while WeChat version 6.2.5 is affected, versions 6.2.6 and greater aren’t. Apple has removed all affected apps from the App Store. Many of the developers of those apps will be issuing updated versions; if you’ve already downloaded the affected apps, experts say it’s important to update them ASAP and change your Apple account password.

An unexpected glitch delayed its release by a week, but Apple has released its watchOS2 operating system for the Apple Watch. Among other updates, the OS offers developers the ability to write apps tailored to the watch’s features, including its heart rate sensor and microphone. Wearers will now be able to use the watch to respond to emails, add up to 12 friends to their contacts list, and use a Discover Card to make payments through Apple Pay.