diff --git a/docs/upgrading/configuration-changes.md b/docs/upgrading/configuration-changes.md
index 73c6dbd..2f82dae 100644
--- a/docs/upgrading/configuration-changes.md
+++ b/docs/upgrading/configuration-changes.md
@@ -72,7 +72,7 @@ The healthcheck section has been removed.
 
 For roles running with a proxy, the healthchecks are performed externally by kamal-proxy, not via internal Docker healthchecks. You can configure the them under [proxy/healthcheck](../../configuration/proxy#healthcheck).
 
-```
+```yaml
 proxy:
   healthcheck:
     path: /health
@@ -80,6 +80,13 @@ proxy:
     timeout: 2
 ```
 
+Please note that the healthchecks will use the `app_port` setting which defaults to port 80. Previously healthchecks defaulted to port 3000. You can change this back with:
+
+```yaml
+proxy:
+  app_port: 3000
+```
+
 ### Non-proxy roles
 
 For roles that do not run the proxy, you can set a custom docker healthcheck via the [options](../../configuration/roles#custom-role-configuration).