Microsoft showcased Windows 10 for phones at their press event last month, alongside all the goodies Windows 10 for desktop will offer. The update to Microsoft's struggling operating system will bring some handy new features, such as universal apps, built-in Office, improved action center, and more. The Technical Preview for phones is expected to roll out sometime this month and will even hit devices with 512MB of RAM, albeit with limited features -- there's no word on the exact availability of the preview at the moment.
Recently, a curious Twitter user pinged Microsoft's Gabriel Aul asking if Lumia Denim will be a requirement to upgrade to the latest Windows 10 for phones, and the answer was no. Aul says, "Denim is not a requirement to upgrade" so most users will be able to get the taste of Windows 10 for phones on their existing handsets whether they are on Denim or the previous version. Microsoft would have quite a handful of angry testers if they made Denim a prerequisite for Windows 10, considering Denim isn't available on every eligible Windows Phone device yet.
@ReinerVergara No, Denim is not a requirement to upgrade
— Gabriel Aul (@GabeAul) February 10, 2015