Hi uroni,
Your client installer stopped on my ocroid-c2 
Verifying archive integrity… All good.
Uncompressing UrBackup Client Installer for Linux 100%
Installation of UrBackup Client 2.0.33… Proceed ? [Y/n] Y
Uncompressing install data…
Detected Debian (derivative) system
Detected systemd
Cannot run UrBackup client on this server. CPU architecture aarch64 not supported. Stopping installation.
Compiling from source works; I switched back.
If you need more information (debugging installer log etc.) just let me know.
Bob