change package version
diff --git a/date.go b/date.go
index 8ae4cc6..5368da3 100644
--- a/date.go
+++ b/date.go
@@ -46,7 +46,7 @@
 // # time in UTC encoded as 64-bit long milliseconds since epoch
 // ::= x4a b7 b6 b5 b4 b3 b2 b1 b0
 // ::= x4b b3 b2 b1 b0       # minutes since epoch
-func (d *Decoder) decDate(flag int32) (time.Time, error) {
+func (d *Decoder) decDate(flag int32) (interface{}, error) {
 	var (
 		err error
 		l   int
@@ -64,6 +64,8 @@
 	}
 
 	switch {
+	case tag == BC_NULL:
+		return nil, nil
 	case tag == BC_DATE: //'d': //date
 		s = buf[:8]
 		l, err = d.next(s)