diff --git a/NEWS b/NEWS
index 43610a7..f4a509a 100755
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,9 @@ Release 2.0.2
    use of the sys:simple-int32-vector type.  Patch supplied by
    Martin Simmons from LispWorks.
 
+ * Minor fix to prevent style-warnings for implementations with no
+   support for md5sum-string.
+
 
 Release 2.0.1
 =============
diff --git a/md5.lisp b/md5.lisp
index 1cc2bc9..b1dae39 100755
--- a/md5.lisp
+++ b/md5.lisp
@@ -676,7 +676,8 @@ positions in the string, not to octets in the resulting binary
 representation.  The permissible external format specifiers are
 determined by the underlying implementation."
   (declare (optimize (speed 3) (safety 3) (space 0) (debug 1))
-           (type string string) (type fixnum start))
+           (type string string) (type fixnum start)
+           (ignorable external-format))
   (locally
     (declare (optimize (safety 1) (debug 0)))
     #+cmu