diff --git a/schemas/mail/mailext.json b/schemas/mail/mailext.json
index c856469..30ef698 100644
--- a/schemas/mail/mailext.json
+++ b/schemas/mail/mailext.json
@@ -11351,8 +11351,8 @@
             {
               "type": "string",
               "name": "key",
-              "description": "Unique tag identifier (must use only alphanumeric characters).",
-              "pattern": "^[$a-zA-Z0-9]+$"
+              "description": "Unique tag identifier (will be converted to lower case). Must not include <value>()<>{/%*\"</value> or spaces.",
+              "pattern": "^[^ ()/{%*<>\"]+$"
             },
             {
               "type": "string",
@@ -11379,8 +11379,8 @@
             {
               "type": "string",
               "name": "key",
-              "description": "Unique tag identifier.",
-              "pattern": "^[$a-zA-Z0-9]+$"
+              "description": "Unique tag identifier (will be converted to lower case). Must not include <value>()<>{/%*\"</value> or spaces.",
+              "pattern": "^[^ ()/{%*<>\"]+$"
             },
             {
               "type": "object",
@@ -11413,7 +11413,8 @@
             {
               "type": "string",
               "name": "key",
-              "pattern": "^[$a-zA-Z0-9]+$"
+              "description": "Unique tag identifier (will be converted to lower case). Must not include <value>()<>{/%*\"</value> or spaces.",
+              "pattern": "^[^ ()/{%*<>\"]+$"
             }
           ]
         }