Update dovecot version to 2.3.20

[akhil1508]

Classification

• [ X] Feature/Enhancement

Reproducibility

Please delete options that are not relevant.

• [X] Always

• Docker information

  docker info
  docker images mailserver2/mailserver --digests --filter "dangling=false"

Description

Dovecot 2.3.14 onwards supports stuff like environment variables in config. We are still using 2.3.13 over here. I think we can update the image to 2.3.20 which is the latest stable version.

• I see it uses debian and apt-get to install so the version is coming from there.
  • Perhaps we add dovecot repositories that have latest version to handle this?

[ksylvan]

Closing this. The latest mailserver2/mailserver image incorporates dovecot-2.3.19 and will keep updating as the base Debian image is updated. We want the most stable and tested together package sets.