diff --git a/collects/mzlib/contract.ss b/collects/mzlib/contract.ss
index 9b447e4..95137d1 100644
--- a/collects/mzlib/contract.ss
+++ b/collects/mzlib/contract.ss
@@ -9,9 +9,6 @@ add struct contracts for immutable structs?
 
 (module contract mzscheme
   
-  ;; no bytes in v206
-  (define (bytes? x) #f)
-  
   (provide (rename -contract contract)
            ->
            ->d