Every six months, along with the regular patches, Microsoft releases new-feature updates. This makes the old Service Patch (SP) model look like slow motion. No enterprise desktop manager wants to upgrade every user’s desktop that often, so they ignore those new-feature updates — until they can’t. In the case of Windows 10, they only have 18 months before any new features are no longer supported. At that point, desktop managers are forced into upgrades. The grumbling has been loud.