Bitninja EXPKEYSIG 4AC1BB4C7F8B47DC or KEYEXPIRED 1684660916

When updating Bitninja on your Debian based server, you experience the error
GPG error: http://apt.bitninja.io/debian bitninja InRelease: The following signatures were invalid: EXPKEYSIG 4AC1BB4C7F8B47DC Heimdall.IO (Heimdall.IO Repository key) packaging@haimdall.io

Solution:

You can update your BitNinja GPG key with this command:

apt-key adv --keyserver keyserver.ubuntu.com --recv-key 7F8B47DC

After that, do an apt update && apt upgrade again.

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