Official support for Windows 8.1 ended on , and Microsoft no longer provides direct ISO downloads for this version on its main software pages. Official Download Methods
A "Windows 8.1 Pro September 2019" ISO typically refers to a or a standard ISO that has been updated with patches released through September 2019. Windows 8.1 Pro ISO September 2019 Free Download
: Previously hosted the Media Creation Tool for downloading Pro and Home editions. Official support for Windows 8
: Subscribers can still access legacy ISOs for various editions, including Pro and Enterprise, which often include official SHA-1 hashes for security verification. including Pro and Enterprise
While direct links are largely discontinued, you can still find official Windows 8.1 images through these Microsoft-managed channels: