Serenum are currently in beta.
You can check it out at serenum.org/beta. The source code can be located at codeberg.org/serenum/website.
You can also find the new and updated API at codeberg.org/serenum/api. The beta version of Serenum does not use this API, but the stable version of Serenum will. It will be released in 2022.
You can visit our project management page while you're waiting.