Ok, I digged deeper into the issue.
It seems that the current apt priority of debian is still pointing to the old stable version
apt-cache madison crowdsec
crowdsec | 1.5.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.5.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.5.0 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.6-6~deb12u1 | https://ftp.debian.org/debian bookworm/main amd64 Packages
crowdsec | 1.4.6 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.5 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.4 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.3 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.3.4 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.3.3 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.3.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.3.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.3.0 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.2.3 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.2.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.2.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.2.0-1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main amd64 Packages
crowdsec | 1.4.6-4 | https://ftp.debian.org/debian bookworm/main Sources
crowdsec | 1.4.6-6~deb12u1 | https://ftp.debian.org/debian bookworm/main Sources
crowdsec | 1.2.0-1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.2.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.2.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.2.3 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.3.0 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.3.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.3.2 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.3.3 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.3.4 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
crowdsec | 1.4.1 | https://packagecloud.io/crowdsec/crowdsec/debian bookworm/main Sources
so I simply added the packagecloud entry to the top of /etc/apt/sources.list and removed /etc/apt/sources.list.d/crowdsec_crowdsec.list
After that version 1.5.2 was taken as the latest and had been updated. Also all directories and plugins are correct.
but now, when I test the mail plugin the mail is sent correctly but the log gives me an error:
DEBU[0001] received EOF, stopping recv loop err="rpc error: code = Unavailable desc = error reading from server: EOF"
DEBU[0001] plugin process exited path=/usr/lib/crowdsec/plugins/notification-email pid=2280226
DEBU[0001] plugin exited