San Francisco, Oct 19 : Apple has stopped code signing for iOS 15.0.1, effectively blocking downgrades to the operating system version released in October. According to AppleInsider, the halt to code signing arrives just under three weeks after iOS 15.0.1 was issued to patch a number of iOS 15 launch bugs, including a problem that prevented users from unlocking iPhone with Apple Watch. Other bugs, like a "storage full" alert and a reported lock screen bypass, were also remedied with the minor point release. A second update, iOS 15.0.2, was pushed out last week with additional fixes for the Find My app, CarPlay and more. Apple debuted its next-generation mobile operating system in late September, introducing iPhone users to a slew of new features, improvements and user interface modifications. Tentpole features include Live Text and Visual Look Up, Focus, upgraded Apple Maps, Health app updates, iCloud+ integration, a Safari redesign and more, the report said. Apple routinely stops signing legacy code after the release of a new iOS build to protect customers from nefarious actors attempting to take advantage of newly discovered vulnerabilities. Preventing users from downloading older code also allows Apple to keep more iOS devices on the latest, feature-rich software, as per the report. With Apple no longer signing iOS 15.0.1 code, the only viable release is iOS 15.0.2, but that will change in the near future. On Monday, the iPhone maker issued a release candidate for iOS 15.1, which will deliver promised features like SharePlay and Wallet support for Covid-19 vaccination cards. /IANS