We strongly recommend upgrading! We’ve packed lots of improvements into the release that will increase your efficiency running checks and make building custom style sheets easier. You can see more of what PerfectIt 5 has to offer here.
Please note that updates for our Windows Edition are not mandatory or automatic, so you can continue without upgrading if you choose to. However, staying current with the latest release is the best way to ensure you save time and deliver the best documents. Instructions for upgrading are here.