A new Windows Phone 8.1 leak has popped up online, showing us what to expect from the upcoming update in terms of features.

Windows Phone 8.1 is the next major update for Microsoft's operating system and it is highly anticipated by Windows Phone users. The new version is expected to bring notable improvements over the current Windows Phone 8 version and deliver better features that would bring Microsoft's platform more on par with rival operating systems such as Android and iOS.

Microsoft recently released its Windows Phone 8.1 Software Development Kit (SDK) to developers, and it was only a matter of time until leaks started to emerge. One developer over on Reddit has been keeping tabs on all updates noticed so far, and the upcoming OS version definitely looks promising.

One of the biggest changes with the upcoming update seems to consist of Universal applications, a feature that was previously missing from Windows Phone 8.1. Both iOS and Android already use this functionality, allowing devs to come up with universal apps that work for phones and tablets alike.

With the new Universal applications feature, developers will be able to build Windows Store and Windows Phone Store apps using the same HTML and JavaScript code, signaling a step forward toward a potential merger between Windows Phone and Windows RT.

Aside from Universal application, Windows Phone 8.1 will also add the ability to change the default messaging app, install apps on SD card via Storage Sense, monitor battery life via Battery Power Sense, and more.

Another notable change will reportedly center on the "Back" button, which will put an app into the background instead of closing it altogether. Users will have to swipe down from multitasking mode in order to close the app, similarly to how the process works on iOS 7. There are also several other changes present in the new build, as detailed in the Reddit post (link in third paragraph).

The leaks so far still show no trace of the much-rumored Cortana voice assistant, but that doesn't necessarily mean that it's not happening. News about Cortana have emerged on several occasions in the past and Microsoft is expected to showcase it at its Build conference in April, alongside the new Windows Phone 8.1.