When you install Directory Opus for the first time, you will be running on a Stock certificate. This certificate allows you to evaluate Opus Light and Opus Pro for up to 30 days, switching between the two editions at any time via the Licence Manager (Help > Licence Manager, on the right of the default toolbars).
The Stock certificate only lasts for 30 days, and the Licence Manager may appear from time to time (especially towards the end of the period) to remind you.
To evaluate Opus Pro for an additional 60-days (up to 90 days in total), and also delay the reminders, you can request an Evaluation certificate. You can do this by clicking the button in the Licence Manager, or via this link.
After requesting an Evaluation certificate, you will be emailed a file which you can install in the Licence Manager to unlock the longer evaluation period. (Double-clicking the file will usually install it automatically, as a shortcut.)
The longer Evaluation certificate switches you into Opus Pro mode, if you weren't already. While we think 30 days is long enough to decide on Opus Light, the Pro edition is more complex and so we give you longer (up to 90 days) to test-drive it and to decide if the extra features are things you need compared to the Light edition. If you ultimately decide to purchase Opus Light, the program will switch back to that edition when you install your purchased licence.
Evaluation certificates also unlock the Advanced FTP add-on so that you can try it during the evaluation period.