diff --git a/protocol/errors.json b/protocol/errors.json
index 0af182d..fba1b0f 100644
--- a/protocol/errors.json
+++ b/protocol/errors.json
@@ -89,7 +89,11 @@
 
   "41001": "push device registration expired",
 
-  "42200": "Unprocessable entity",
+  "42200": "unprocessable content",
+  "42210": "content rejected (unspecified)",
+  "42211": "content rejected by before publish rule",
+  "42212": "content rejected by validation",
+  "42213": "content rejected by moderation",
 
   "42910": "rate limit exceeded (nonfatal): request rejected (unspecified)",
   "42911": "max per-connection publish rate limit exceeded (nonfatal): unable to publish message",