In my environment, home dirs are mounted via NFS, so users will be able to login to several different workstations and always get their stuff transparently. However, sometimes, a user would login to a workstation which had a different version of kde installed (oldstable system, instead of stable one), and in the past this led to several weird problems due to different KDE versions messing around with files in $KDEHOME.
To solve this issue, I used to set KDEHOME (system wide) to something like ~/.kde.jessie or ~/.kde.wheezy (instead of default ~/.kde) with an export within /usr/env. However, I have just finished installing my first stretch desktop, and I discovered that all this is plain old stuff with Plasma 5, which doesn't use KDEHOME anymore.
How could I avoid conflicts between different versions of kde from now on?