"We plan to upgrade all Windows Phone 8 devices to Windows 10 in the future :)"
Of course, this appears to be more of an assurance that every Lumia-branded phone will get the upgrade than every Windows Phone 8 device, as backed up by an earlier tweet that read:
"There will be Windows 10 upgrades for all Lumia Windows Phone 8 devices."
If you're wondering why there would be any doubt, the original question that prompted the latest statement from Microsoft's Twitter account made reference to Windows Phone 7.8. Microsoft disappointed many in the switch from Windows Phone 7 to Windows Phone 8 at the beginning of 2013 by not offering an upgrade path from one to the other.
Instead, Microsoft started afresh with brand new Windows Phone 8 hardware and released Windows Phone 7.8 for existing Windows Phone 7 handsets. This was something of a compromise, with a couple of token features from Windows Phone 8 layered over the same underpinnings as Windows Phone 7.5.
Windows Phone 7 was built on a completely different kernel to Windows Phone 8, though, whereas Windows 10 shouldn't be such a radical departure from Windows Phone 8 deep down.
Read More: Nokia Lumia 735 review
Via: Windows Central