my @comments = (
  '# Version: 1.11',
  '* Version: 1.11',
  'Version: 1.11',
  '/* Version: 1.11',
);
foreach(@comments) {
  print m<^ (?: \# | /? \* )?
            \s* version: \s+
            (\d+ (?:\.\d+)+ ) >ix,$/;
}

__output__

1.11
1.11
1.11
1.11