Yesterday, details emerged of a new 'Windows 10 Upgrade Advisor' app, including screenshots explaining that the app "provides information about upgrading to Windows 10 and helps you prepare your phone to install the upgrade."
Today, the app's listing was spotted by Gustave M (@gus33000) on the Windows Store - but it's not yet available to download.
Listed as 'Upgrade Advisor Beta', the app was published by Microsoft's 'Internal Beta Account', so it can't be installed by those without the right permissions to do so. The app's description reads:
The Windows 10 Mobile Upgrade Advisor app will tell you if your Windows 8.1 phone is eligible for upgrade to Windows 10 Mobile. It can also help free up space on your phone so you're ready for the upgrade. When you open the app, it checks your phone and lets you know if it's eligible to upgrade, if an update is required before you can upgrade, or if your phone can't be upgraded. See windows.com/mobilespecs for more information.
If your phone is eligible for the upgrade, you may need to free up some space to get it. The app will recommend files, such as videos or photos, that you can temporarily move to OneDrive or an SD card, if you have one installed. Accept the recommendations, or change which files you want to move. You can also delete some files, if you want. If you move files to OneDrive, you need to use the app to restore files back to your phone after Windows 10 Mobile is installed.
Microsoft had originally planned to begin upgrading existing Windows Phone 8.1 handsets to Windows 10 Mobile last month, but delayed its release until early this year. However, upgrades are expected to begin next week, although one carrier said yesterday that it has already begun the rollout.