What the difference between Perpetual and Annual?

What the difference between Perpetual and Annual?

Chemdraw comes in two licensing models – term (e.g. annual) and perpetual. You can choose to pay maintenance on perpetual licensing – most people don’t, but why you might is that it keeps your support active, and also keeps you eligible for upgrades. Otherwise – you will reach a point where your software is not supported on the latest OS release on your computer.