diff --git a/lib/config-os400.h b/lib/config-os400.h
index d2cb1caff..bde4f0b33 100644
--- a/lib/config-os400.h
+++ b/lib/config-os400.h
@@ -425,8 +425,8 @@
 /* Define if you can safely include both <sys/time.h> and <time.h>. */
 #define TIME_WITH_SYS_TIME
 
-/* to enable alt-svc */
-#define USE_ALTSVC 1
+/* Define to enable alt-svc support (experimental) */
+#undef USE_ALTSVC
 
 /* Version number of package */
 #undef VERSION
diff --git a/packages/OS400/ccsidcurl.c b/packages/OS400/ccsidcurl.c
index eae2c5751..a4cae27ee 100644
--- a/packages/OS400/ccsidcurl.c
+++ b/packages/OS400/ccsidcurl.c
@@ -1132,7 +1132,12 @@ curl_easy_setopt_ccsid(CURL * curl, CURLoption tag, ...)
   if(testwarn) {
     testwarn = 0;
 
-    if((int) STRING_LASTZEROTERMINATED != (int) STRING_ALTSVC + 1 ||
+    if(
+#ifdef USE_ALTSVC
+       (int) STRING_LASTZEROTERMINATED != (int) STRING_ALTSVC + 1 ||
+#else
+       (int) STRING_LASTZEROTERMINATED != (int) STRING_DOH + 1 ||
+#endif
        (int) STRING_LAST != (int) STRING_COPYPOSTFIELDS + 1)
       curl_mfprintf(stderr,
        "*** WARNING: curl_easy_setopt_ccsid() should be reworked ***\n");