diff --git a/overlay.nix b/overlay.nix
index 399e827..5535291 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -1,6 +1,6 @@
 self: super:
 
 {
-    pegasus = super.callPackage ./pegasus/default.nix {};
+    pegasus = super.callPackage ./pegasus/default.nix { crystal = super.crystal_0_31; };
     blog = super.callPackage ./blog/default.nix {};
 }