The console wars are heating up once again. Rumors have swirled for months about an upgraded PlayStation 4, now believed to be codenamed "NEO," coming from Sony. Similar rumors continue to circulate around the Xbox One as well, making it seem increasingly likely that Microsoft and Sony are looking to bring new and improved versions of their existing consoles to market.

Despite Xbox head Phil Spencer saying in an interview that he wasn't a fan of the idea of an Xbox One and a half, it does seem like Microsoft is up to something. The Verge reports that its sources have confirmed that Microsoft has been testing out a variety of "prototype" Xbox devices. Some of the prototypes, the site reports, have been tested with upgraded components similar to what would be used to improve a PC gaming machine.

When combined with recent evidence of unannounced filings with the FCC from Microsoft that line up closely with similar filings for components included in the Xbox One, it seems there may be more truth to these rumors than originally believed.

What exactly all of the rumors mean, however, is another story. Spencer has gone on record to say that if there was to be a new version of the Xbox One, it would be "a really substantial change for people — an upgrade."

An upgrade could come in a number of forms, including everything from wireless chip filed with the FCC to improved graphical power and performance. Rumors about Sony's upgraded PS4 console revolve around the company looking to improve its hardware in time for the launch of the PlayStation VR. Aside from simply being an improvement for improvement's sake, it's unclear what Microsoft would be looking to achieve with an Xbox One upgrade, considering it won't be competing in the VR space. Microsoft does have the Hololens headset to consider, but it remains unclear how that piece of technology would work with the Xbox One.

If an upgrade is released, it also raises questions about compatibility. New PS4 NEO rumors state that all PS4 games will work on the original PS4 hardware, but that developers will also have to scale up their games in the future for the improved console as well. If Microsoft is also poised to release an upgraded Xbox One, it will have to answer that question as well.

Many of these mysteries will likely be solved at this summer's E3 expo, where Sony, Microsoft and Nintendo will make all their major announcements for the year.