diff --git a/lib/zstd.h b/lib/zstd.h
index 0de81f3ac..3e977aa09 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -620,12 +620,13 @@ typedef enum {
      * ZSTD_c_forceMaxWindow
      * ZSTD_c_forceAttachDict
      * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
-     * note : never ever use experimentalParam? names directly
+     * note : never ever use experimentalParam? names directly;
+     *        also, the enums values themselves are unstable and can still change.
      */
      ZSTD_c_experimentalParam1=500,
      ZSTD_c_experimentalParam2=10,
      ZSTD_c_experimentalParam3=1000,
-     ZSTD_c_experimentalParam4
+     ZSTD_c_experimentalParam4=1001
 } ZSTD_cParameter;