Microsoft's Xbox head Phil Spencer seemed to be pretty clear when he said that there wasn't going to be an "Xbox One-and-a-Half" incremental upgrade to the Xbox One. This came on the heels of escalating rumors about the PlayStation 4.5/4K, and many took it to mean that it would be a while before we saw new Xbox hardware.
That may not be the case, however. While it's still only rumor at this point, it's been suggested that we could see an Xbox revamp in the not too distant future. It's even possible that it will come in a few months at E3.
According to Destructoid, Microsoft has filed two unannounced projects with the FCC; this heavily suggests new hardware, since the FCC requires all data transmission devices to be filed (and this would include devices such as gaming hardware that transmits game data over a WiFi network). The details of the filings remain private, but the company is not able to hide the availability dates for the new devices: June 25, 2016 for one, and June 29, 2016 for the other. As Destructoid pointed out, this is shortly after E3.
Looking at what Phil Spencer actually said at last month's Build Developers Conference, he didn't explicitly rule out new hardware; he simply stated that new Xbox hardware would be more than just an incremental upgrade. Looking at his offical statement, Spencer said:
“I’m not a big fan of Xbox One and a half. If we’re going to move forward, I want to move forward in big numbers… For us, our box is doing well. It performs, it’s reliable, the servers are doing well. If we’re going to go forward with anything, like I said, I want it to be a really substantial change for people–an upgrade.”
He didn't have any announcements to make about new hardware at the time, but it's pretty common for companies to downplay or outright deny projects that are in development until the time of the official announcement arrives. Even the Nintendo NX, which has been referenced by the company a few times but still hasn't had an official unveiling, sees rumors running rampant because the company refuses to comment on what may or may not be accurate in the rumor mill.
A reference to "User Manual 1525" in the FCC filings could be a reference to the current Xbox One, as its FCC-approved model number is 1525. This would suggest that one of the filings could just be a slimmed-down version of the current Xbox One hardware, so we might see an E3 announcement of the Xbox One Slim at perhaps a lower price point. It might even be announced with a new or redesigned wireless peripheral, which would be the other filing. While that's not nearly as exciting as a new Xbox model, it would fit in with Spencer's comments (since it would just be a physical redesign and not "going forward" with new features) and would be something that a lot of console owners have already been expecting. But what if that's not what the filings are for?
While the PlayStation 4 has PlayStation VR on the way, there is currently no equivalent for the Xbox One. Microsoft does have a partnership with Oculus Rift, so it's possible that Microsoft is planning a VR-ready Xbox console (and perhaps a custom Oculus-powered peripheral) that will feature more power, PC compatibility and full VR support. It might even see more along the lines of hardware-based backwards compatibility, since that's also been a big focus of Xbox announcements as of late. The combination of power + PC cross-support + VR (and possibly hardware-driven backwards compatibility) could be seen as more than just a half-step forward, and it would give Microsoft a way to compete directly with the PS4K and PSVR.
Of course, it's also possible that the two FCC filings are unrelated to the Xbox One. Microsoft has other hardware offerings aside from the Xbox One, so it's possible that the filings could be related to the Surface product line or possibly even the long-rumored Surface Phone. If the filings are Xbox related, we should find out in just a few months one way or the other.
Microsoft currently has no official plans for a follow-up or revision to the Xbox One, but Screen Rant will keep you updated if and when this changes.