The mailserver that we use here is Kopano Core Community Edition, it has alot of features and works very well with the setup we got.
One ”problem” with CE is upgradeing, some packages sometimes get obsoloteted but still has dependecies that brakes yum yum to upgrade. From 8.4.90 to 8.5.80 we had some problems with libkcl0 that wasnt aviable in the new 8.5 but many dependencies in the old. A rpm -Uvh –nodeps was necessary to resolve issues and then remove libkcl0 because it wasnt needed any more.
In all this I set up a Kopano Core CE yum repo for RHEL7 on my webserver, updates becomes easier for me and if someone wants to use it feel free to add this to your repolist.
Updates to this repo will be once every two weeks or so, drop me a line if I have missed out something. (When writing this there is no easy way of scripting around getting the correct urls from download.kopano.io automatically.)
[Kopano] name=Kopano CentOS 7 Repo baseurl=https://cname.se/repo/kc/x86_64 gpgcheck=0 enabled=1
20180201 Kopano 220.127.116.11 is broken, do not use it!