The mobile device is running a version of iOS that is older than version 5.0.1. Version 5.0.1 contains security-related fixes for the following vulnerabilities :
Apple iOS and Mac OS X CFNetwork Cross-Domain Information Disclosure Vulnerability (CVE-2011-3246)
Apple iOS FreeType Multiple Memory Corruption Vulnerabilities (CVE-2011-3439)
Apple iOS Code Signing Security Bypass Vulnerability (CVE-2011-3442)
Apple iOS Libinfo Component Information Disclosure Vulnerability (CVE-2011-3441)
Apple iPad Passcode Lock Local Security Bypass Vulnerability (CVE-2011-3440)
Binary data apple_ios_501_check.nbin