There has been some complaints about AirPlay video playback in the 2 months since the release of iOS 5.1, as well as a bug that prevented the new iPad from switching between 2G and 3G networks. The new update, iOS 5.1.1 will improve these problems as well as the reliability of using the HDR option for pics snapped with the Lock Screen camera shortcut.
And if you’ve ever seen an “Unable to purchase” alert after successfully purchasing something on iOS, good news: The 5.1.1 update also resolves that issue.
If you have a jailbroken iPhone, iPad or iPod Touch running the latest software, you can upgrade to iOS 5.1.1 without fear of losing your jailbreak. According to RedmondPie, you can update to iOS 5.1.1 and still have a jailbroken phone, provided if you use the latest version of RedSn0w.
Allow your iGadget to update to the latest version of iOS 5.1.1, but afterwards, download or keep iOS 5.1 handy (you can still get it from Apple if you don’t). Open Redsn0w and make sure you specify it needs to run the iOS 5.1 file–essentially, it’s repeating the previous software jailbreak. You also need to make sure Redsn0w installs Cydia too (there’s a checkbox for that).