The official list of Microsoft-compatible devices with the upgraded Windows 10 Mobile has phones for less than the capacity of RAM for 1GB making devices that have 512MB Ram is eligible for the upgrade despite the fact that many insiders claim that Windows 10 Mobile is able to work with random memory capacity less without problems.
That's not all. Some qualifying setups for upgrade will not get it despite the fact that the required specifications are available, one of these devices is the HTC phone M8 this device features 2GB of RAM and this makes HTC One the most powerful M8 from most of the devices on the list of Microsoft with it You will not get the update.
Microsoft did not specify the reason for not receiving the phone to upgrade, and generally the phone users now resentful of the two companies because of this act and perhaps anger could push Microsoft's update made available by the end of the day.