I bought the Supporters Edition but the advanced features are still blocked. What can it do?

This happens because you still use the Community Edition even if you have purchased the Supporters Edition.

You can check this in the info section:

If you're using the Supporters Edition, you should see the suffix SE beside the version number:

Instead, if you are still using the Community Edition, you see the suffix CE beside the version number:

In conclusion: bibisco Supporters Edition and bibisco Community Edition are different applications, so you have to download, install and launch Supporters Edition as described in the link here: How to upgrade from Community to Supporters Edition.

In particular, pay attention to the name of the installation file. If the file has an SE extension (for example, bibisco-win32-x64-2.4.0-SE-install.exe) it concerns the Supporters Edition, while if it has a CE extension (for example, bibisco-win32-x64-2.4.0-CE-install.exe), it concerns the Community Edition.