while ( <INFILE> ) {
	next if not /ver = '(.*?)'/;
	$old_version = $1;
	close INFILE;
	last;
}

##</code><code>##

{
	open my $fh, '<', $filename
		or die "Can't open $filename: $!\n";

	while ( <$fh> ) {
		next if not /ver = '(.*?)'/;
		$old_version = $1;
		last;
	}
}

##</code><code>##

use List::Util qw( first );

my $old_version = do {
	open my $fh, '<', $filename
		or die "Can't open $filename: $!\n";

	first { /ver = '(.*?)'/ } <$fh>;
};