diff --git a/changelog.d/14358.doc b/changelog.d/14358.doc
new file mode 100644
index 0000000000..a9b910878d
--- /dev/null
+++ b/changelog.d/14358.doc
@@ -0,0 +1 @@
+Replace references to legacy metrics `synapse_admin_mau` with new metric names.
diff --git a/docs/usage/administration/monthly_active_users.md b/docs/usage/administration/monthly_active_users.md
index d4e9037284..b1da6f17c2 100644
--- a/docs/usage/administration/monthly_active_users.md
+++ b/docs/usage/administration/monthly_active_users.md
@@ -73,12 +73,12 @@ When a request is blocked, the response will have the `errcode` `M_RESOURCE_LIMI
 
 Synapse records several different prometheus metrics for MAU.
 
-`synapse_admin_mau:current` records the current MAU figure for native (non-application-service) users.
+`synapse_admin_mau_current` records the current MAU figure for native (non-application-service) users.
 
-`synapse_admin_mau:max` records the maximum MAU as dictated by the `max_mau_value` config value.
+`synapse_admin_mau_max` records the maximum MAU as dictated by the `max_mau_value` config value.
 
 `synapse_admin_mau_current_mau_by_service` records the current MAU including application service users. The label `app_service` can be used
 to filter by a specific service ID. This *also* includes non-application-service users under `app_service=native` .
 
-`synapse_admin_mau:registered_reserved_users` records the number of users specified in `mau_limits_reserved_threepids` which have
+`synapse_admin_mau_registered_reserved_users` records the number of users specified in `mau_limits_reserved_threepids` which have
 registered accounts on the homeserver.