It was introduced long time ago in Angie fork with much better support.

Here's the docs for the Angie's version of the http_acme module:

https://en.angie.software/angie/docs/configuration/modules/h...

The original announcement of Angie ACME:

Angie, fork of Nginx, supports ACME - https://news.ycombinator.com/item?id=39838228 - March 27, 2024 (1 comment)

Per above, it looks like ACME support was released with Angie 1.5.0 on 2024-03-27.

BTW, if you don't care about ACME, and want the original nginx, then there's also the freenginx fork, too:

Freenginx: Core Nginx developer announces fork - https://news.ycombinator.com/item?id=39373327 - (1131 points) - Feb 14, 2024 (475 comments)