Hello Paweł Bazylewicz - Perceptus
To upgrade from Windows 11 Home to Pro compliantly as a non-profit, you must strictly follow the recommendation to use one of the following valid paths:
The Specific "Home to Pro" SKU: You must request the SKU ending in :0002 (often labeled Windows 11 Home to Pro Upgrade for Microsoft 365 Business). This license is explicitly designed to bridge the gap from Home to Pro.
GGWA (Get Genuine Windows Agreement): If the :0002 SKU is unavailable in your region's charity price list, you must purchase a GGWA license. This is a full legalization license that does not depend on a prior qualifying OS.
Do not purchase the :0003 license for Home devices.
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VP