diff --git a/ggml.h b/ggml.h
index c25415ae3..26654fc8e 100644
--- a/ggml.h
+++ b/ggml.h
@@ -1378,7 +1378,7 @@ extern "C" {
             float                 ext_factor,
             float                 attn_factor,
             float                 beta_fast,
-            bool                  beta_slow,
+            float                 beta_slow,
             float                 xpos_base,
             bool                  xpos_down);