is the original release of Windows 10, also known as the "July 2015 Update" or "RTM" (Release to Manufacturing). Its build number is 10240 . Unlike later updates (1511, 1607, etc.), 1507 has no major service pack or cumulative update baked into the base ISO—it is the pure, unaltered launch version.
Given that version 1507 is nearly a decade old and no longer receives security patches, why would a user seek out this specific ISO? windows 10 version 1507 iso