diff --git a/compose.yml b/compose.yml
index 9d73d7b..5e86d2a 100644
--- a/compose.yml
+++ b/compose.yml
@@ -32,7 +32,18 @@ odoo:
           #ProxyPass /longpolling/ http://odoo:8072/longpolling/
           #ProxyPassReverse /longpolling/ http://odoo:8072/longpolling/
 
-        ssl: letsencrypt
+        ssl:
+          letsencrypt:
+            challenge-type: http  ## if 'dns', be sure to prepare 'env' correctly
+            # env:
+            #   ovh:
+            #     ## see: https://api.ovh.com/g934.first_step_with_api
+            #     entrypoint: ovh-eu
+            #     application:
+            #       key: XXX
+            #       secret: YYY
+            #     consumer_key: ZZZ
+        # ssl: true  ## simple auto-signed SSL certificates
         # ssl:
         #   ca-cert:
         #     -----BEGIN CERTIFICATE-----
@@ -72,20 +83,23 @@ odoo:
 frontend:
   charm: apache
   relations:
-    letsencrypt-dns:
+    cert-provider:
       letsencrypt
 
 
 letsencrypt:
   options:
     email: admin@0k.io
-    ovh:
-      ## see: https://api.ovh.com/g934.first_step_with_api
-      entrypoint: ovh-eu
-      application:
-        key: XXX
-        secret: YYY
-      consumer_key: ZZZ
+    ## General configuration for this service will be applied to all linked
+    ## services.
+    # env:
+    #   ovh:
+    #     ## see: https://api.ovh.com/g934.first_step_with_api
+    #     entrypoint: ovh-eu
+    #     application:
+    #       key: XXX
+    #       secret: YYY
+    #     consumer_key: ZZZ
 # mattermost:
 #   charm: mattermost
 #   relations: