If you are a business with an active Software Assurance agreement or a Volume Licensing agreement that dates back to 2015, you can download the original Windows 10 Enterprise 1507 ISO from the VLSC portal. However, the version was rarely distributed via VLSC; most volume customers got Enterprise.
Q: Can I upgrade from Windows 10 Pro 1507 to a newer version of Windows 10? A: Yes, users can upgrade from Windows 10 Pro 1507 to a newer version of Windows 10. windows 10 pro 1507 iso download