If you've purchased a subscription but are still limited to 4 boards, you most likely have created multiple workspaces and have selected a workspace that doesn't have a subscription associated with it.
To switch over to another workspace, click the dropdown menu at the upper-left corner of the screen (1) and click on the name of your other workspace (2):
If you have accidentally upgraded the wrong workspace or still are experiencing issues with upgrading, drop us an email or chat with us directly from the app!