Microsoft has posted an end-of-life date for Windows 10 Mobile, though it raises more questions than it answers.

According to Microsoft’s support website, mainstream Windows 10 Mobile support will cease on January 9, 2018. However, the posting also says Microsoft will make extended support updates and security patches available for “a minimum of 24 months after the lifecycle start date” of November 16, 2015.

Stranger still, the support site originally listed an end date of January 8, 2019 when WinBeta discovered it last night, with Microsoft promising updates for “a minimum of 36 months.” Since then, the document has changed to reduce Windows 10 Mobile’s lifespan by one year.

It gets weirder. Although Microsoft has previously said that Microsoft alone would distribute Windows 10 Mobile updates, with wireless carriers playing just a supporting role, the support document suggests otherwise. “The distribution of these incremental updates may be controlled by the mobile operator or the phone manufacturer from which you purchased your phone, and installation will require that your phone have any prior updates,” it says. (Windows Insiders can always install preview builds without going through carriers, though this increases the risk of running into bugs.)

Microsoft’s support site doesn’t shed any light on what will happen after January 2018. We can only speculate that a more significant upgrade for Microsoft’s mobile operating system will arrive, assuming the whole effort hasn’t cratered by then.

Why this matters: Long-lasting hardware support has been a touchy issue for Windows Phones over the years. Windows Phone 7 was a clean break from the old Windows Mobile, and Microsoft famously abandoned Windows Phone 7 users (and the existing app ecosystem) when it moved to Windows Phone 8. With Windows 10 Mobile, Microsoft has repeatedly walked back its upgrade promises for existing phones, and today the only phone running the latest stable operating system are the brand-new Lumia 950 and Lumia 950 XL. With Microsoft’s support document leaving plenty of open questions, Windows phone fans could be reasonably skittish about their upgrade paths from here on.