Apple has released  iOS 5.1 beta for iPhone, iPod touch and iPad, which developers can download from the Apple developer portal, media reported Tuesday. The new version represents the first significant update to iOS 5 since its release in mid-October. BGR Monday posted the full release notes of the software, which developers must sign a nondisclosure agreement to use. The notes do not suggest any major new features in the build, despite anticipation otherwise. According to the release’s What’s New document, iOS 5.1 includes better dictation support for third-party apps. Unfortunately, there’s no word on whether iOS 5.1 mitigates power-related issues that iPhone 4S users are still complaining of. A report from German Mac site Macerkopf.de earlier this month suggested that 5.1 would bring extra features to Siri in the form of hardware controls, letting users adjust things like Wi-Fi and Bluetooth radios through the iPhone 4S voice assistant.