The app is distributed through the [app store](https://apps.nextcloud.com/apps/contacts) and you can install it [right from your Nextcloud installation](https://docs.nextcloud.com/server/stable/admin_manual/apps_management.html).
Release tarballs are hosted at https://github.com/nextcloud-releases/contacts/releases.
If you need assistance or want to ask a question about Contacts, you are welcome to [ask for support](https://help.nextcloud.com) in our Forums or the [IRC-Channel](https://webchat.freenode.net/?channels=nextcloud-contacts). If you have found a bug, feel free to open a new Issue on GitHub. Keep in mind, that this repository only manages the frontend. If you find bugs or have problems with the CardDAV-Backend, you should ask the team at [Nextcloud server](https://github.com/nextcloud/server) for help!
> This is a complicated answer. We did not invent the way contacts works. We are following the official vCard format. This format include a predefined set of properties that other applications/devices supports too (Android, iOS, Windows, Gnome...). Adding a custom property would just make it compatible with Nextcloud and will not be understood by any other clients and make it complicated for us to ensure its sustainability over time.
Long story short, we suggest you use the Notes field to add your custom data :)