In order to update ACDSee Editor, navigate to the Help menu and click the Update button. Once the updating files are downloaded, click Install and follow the on-screen instructions. Also, if you have an older version of the program, you can download and install ACDSee Photo Editor 6.0 from the official web page. Its price is around $59.99.
Unfortunately, you can't update ACD Photo Manager anymore, because it has been replaced by ACDSee 18 which comes packaged with tools that allows you to organize, manage and edit your photos. The developers allows you to upgrade the software only to ACDSee 16. If you want the latest version, you will need to pay around $59.99. I suggest you contact ACD Systems International for further information.