diff --git a/hosts/mail/modules/dovecot.nix b/hosts/mail/modules/dovecot.nix
index dd0e918..3c23a36 100644
--- a/hosts/mail/modules/dovecot.nix
+++ b/hosts/mail/modules/dovecot.nix
@@ -193,6 +193,7 @@ in
         managesieve_logout_format = bytes ( in=%i : out=%o )
       }
 
+      recipient_delimiter = +
       lda_original_recipient_header = X-Original-To
 
       plugin {
diff --git a/hosts/mail/modules/postfix.nix b/hosts/mail/modules/postfix.nix
index ac71d35..bc9d8ee 100644
--- a/hosts/mail/modules/postfix.nix
+++ b/hosts/mail/modules/postfix.nix
@@ -125,6 +125,7 @@ in
       # The extra detail makes trouble shooting easier but also reveals information
       # that is nobody elses business.
       show_user_unknown_table_name = "no";
+      recipient_delimiter = "+";
       compatibility_level = "2";
 
       # bigger attachement size