The iOS mobile operating system developed by Apple Inc. has had a wide range of bugs and security issues discovered throughout its lifespan, ranging from security exploits discovered in most versions of the operating system related to the practice of jailbreaking, as well as bypassing the user's lock screen (known as lock screen bypasses), to issues relating to battery drain, to crash bugs encountered when sending photos or certain Unicode characters via text messages sent through the Messages application, and general bugs and security issues later fixed in newer versions of the operating system.