diff --git a/README.md b/README.md
index 2f51d62..adafdc8 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,12 @@ thanks to its authors!
 ## Known issues
 
 - Userscript limitations
-    - Only `text/gemini` content is shown.
+    - Only `text/gemini` content is shown. Any other MIME types received over
+      Gemini are considered an error.
+    - There is no support for user input (Gemini codes 1\*).
+    - There is no support for client certificates (Gemini codes 6\*).
+    - Opening non-`gemini://` URLs with the userscript might not work correctly
+      in rare cases.
 - Qutebrowser limitations
     - Opening `gemini://` URLs by clicking on them does not work, only opening
       them via the keybinding is possible.