diff --git a/docs/libcurl/opts/CURLOPT_ALTSVC.md b/docs/libcurl/opts/CURLOPT_ALTSVC.md
index 14e3f31f92..8bc2bc6b8e 100644
--- a/docs/libcurl/opts/CURLOPT_ALTSVC.md
+++ b/docs/libcurl/opts/CURLOPT_ALTSVC.md
@@ -60,13 +60,18 @@ int main(void)
 {
   CURL *curl = curl_easy_init();
   if(curl) {
-    curl_easy_setopt(curl, CURLOPT_ALTSVC_CTRL, (long)CURLALTSVC_H1);
+    curl_easy_setopt(curl, CURLOPT_ALTSVC_CTRL, CURLALTSVC_H1);
     curl_easy_setopt(curl, CURLOPT_ALTSVC, "altsvc-cache.txt");
     curl_easy_perform(curl);
   }
 }
 ~~~
 
+# HISTORY
+
+CURLALTSVC_\* macros became `long` types in 8.16.0, prior to this version
+a `long` cast is necessary when passing to curl_easy_setopt(3).
+
 # FILE FORMAT
 
 A text based file with one line per alt-svc entry and each line consists of