diff --git a/tsplotv b/tsplotv
index 23fd9a8..d741d14 100755
--- a/tsplotv
+++ b/tsplotv
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w 
+#!/usr/bin/perl
 
 =head1 NAME
 
@@ -39,7 +39,10 @@ other.
 
 =cut
 
-use strict;
+use v5.20;
+use warnings;
+use experimental qw(postderef);
+
 use TimeSeries;
 use Getopt::Long;
 use Pod::Usage;