Installation & Licensing
The Custom User Profile plugin is a type two add-on, please follow the installation instructions as given by Atlassian: Installation steps via Universal Plugin Manager
Configuration
See CUP - Configuration 1.7 for further information
Profile Completion Assistant
See CUP - Profile Completion Assistant 1.7 for further information
Known Issues
"Profile Updated" by Anonymous due to Confluence Synchronization
When Confluence synchronize against any external user management, all of the newly created and updated users will be displayed under the "All Updates" section of "Recently Updated" macro in Confluence dashboard.
Considering the amount of users Confluence will create or update from the synchronization, it would be better if it is excluded from "All Updates" section. Or at least, Confluence should provide the option to exclude these updates.
Parentheses in filters are treated wrong
Since we have introduced complex filters for your custom landing pages, parentheses in filters are treated as logical characters. So your filter might be broken if you try to filter by attributes containing parentheses.
A workaround would be using the wildcard '?' instead of a parenthesis.
"Unknown macro 'profile'" after removing CUP
The CUP overrides the "profile" macro of Confluence and after uninstalling or disabling CUP Confluence claims the macro to be unknown on pages where it is used:

We are working on a solution but until then the best workaround is to restart Confluence.