diff --git a/docs/libcurl/opts/CURLOPT_HEADEROPT.md b/docs/libcurl/opts/CURLOPT_HEADEROPT.md
index 090781042c..56d205689f 100644
--- a/docs/libcurl/opts/CURLOPT_HEADEROPT.md
+++ b/docs/libcurl/opts/CURLOPT_HEADEROPT.md
@@ -65,7 +65,7 @@ int main(void)
     /* HTTPS over a proxy makes a separate CONNECT to the proxy, so tell
        libcurl to not send the custom headers to the proxy. Keep them
        separate. */
-    curl_easy_setopt(curl, CURLOPT_HEADEROPT, (long)CURLHEADER_SEPARATE);
+    curl_easy_setopt(curl, CURLOPT_HEADEROPT, CURLHEADER_SEPARATE);
     ret = curl_easy_perform(curl);
     curl_slist_free_all(list);
     curl_easy_cleanup(curl);
@@ -73,6 +73,11 @@ int main(void)
 }
 ~~~
 
+# HISTORY
+
+CURLHEADER_\* macros became `long` types in 8.16.0, prior to this version
+a `long` cast is necessary when passing to curl_easy_setopt(3).
+
 # %AVAILABILITY%
 
 # RETURN VALUE