You can install the free poste.io directly from the Docker registry
Repository: https://hub.docker.com/r/analogic/poste.io/
docker run \
-p 25:25 \
-p 80:80 \
-p 443:443 \
-p 110:110 \
-p 143:143 \
-p 465:465 \
-p 587:587 \
-p 993:993 \
-p 995:995 \
-e TZ=Europe/Prague \
-v /your-data-dir/data:/data \
-t analogic/poste.io
If you have further questions please contact us at info@poste.io