Apple released a fifth beta version of iOS 5 to developers today, a change from its usual habit of delivering such betas during the work week.

According to MacRumors, the release notes include some fixes but no major additions, save for a Hearing Aid Mode designed to improve compatibility between iOS devices and hearing aids.

The MacRumors item also says that like the beta 4 release, beta 5 is available as an over-the-air download but that users must first erase all content and settings. Apple suggests, also, that before installing beta 5, users back up devices with iTunes 10.5 beta 4 or through iCloud, and then restore. MacRumors adds, however, that some users have skipped the recommended process and been able to install the new beta version with no problems.

Nate of NatesTechUpdate on YouTube has posted a quick video that looks at some of the tweaks made in beta 5. And BGR has posted the full change log.

The previous beta version of iOS made its way to developers in late July as both a download and an over the air update. It brought with it Wi-Fi syncing for Windows users, the feature that lets users sync their iOS device with their iTunes library minus the cord, as long as it's on the same Wi-Fi network, and plugged into a power source.

Apple typically seeds several beta versions of its major software releases to developers ahead of time to work out any bugs and give the developers time to integrate new features and APIs into their applications.

iOS 5 made its debut at Apple's Worldwide Developers Conference in June. Its headlining feature is an overhaul of the notifications system, alongside a new messaging platform called iMessage that lets iOS users text and chat with each other free of charge. The software is also deeply tied to Apple's upcoming iCloud service, which will be used to ferry photos, applications, and settings back and forth between iOS devices, as well as serve as a free backup solution.

CNET's Josh Lowensohn contributed to this report.