What we know so far about the unusual Windows 10 1909
Microsoft has acknowledged that this fall's "feature upgrade" for Windows 10 will be virtually identical to the already-available version 1903 released in May.
"19H1 and 19H2 share the same servicing content. That means they share the same Cumulative Update package," Dona Sarkar and Brandon LeBlanc, the spokespeople for Microsoft's Windows Insider beta testing program, wrote last week in a post to their group's blog.
Sarkar and LeBlanc referenced 19H1 and 19H2 - better known perhaps as 1903 and 1909, respectively, in Microsoft's four-number labeling format - because their team had just released those builds to the Release Preview ring, where a subgroup of all program participants do a last test of betas.