diff --git a/History.md b/History.md
index b33b310b..865df15a 100644
--- a/History.md
+++ b/History.md
@@ -81,6 +81,7 @@
   * min_threads now set by environment variables PUMA_MIN_THREADS and MIN_THREADS. ([#2143])
   * max_threads now set by environment variables PUMA_MAX_THREADS and MAX_THREADS. ([#2143])
   * max_threads default to 5 in MRI or 16 for all other interpreters. ([#2143])
+  * Configuration: number of workers is read from `WEB_CONCURRENCY` if `workers` isn't set ([#2143])
   * preload by default if workers > 1 ([#2143])
   * Puma::Plugin.workers_supported? has been removed. Use Puma.forkable? instead. ([#2143])
   * `tcp_mode` has been removed without replacement. ([#2169])