Hello,
Sorry for my stupid question, but since many years ago, I have always used plasma 4 on all my OS installed 11 but only 3 with mint, debian, or an other OS Xubuntu with my favorite KDE , plasma 4.. But since the new plasma5 version ..it's possible to renew on plasma4 ? ? ?
I try for explain my reason why usually I have screensaver on plasma4 with more/less 250 models in this, my favorite are "the clock" but it's not the model for anyone..
I'm sure I don't want critical opinion , just for this stupid question it's possible or not to change again plasma 5 for plasma4 ? All practice for they 2 plasma it's completly correct , effects etc etc except for the xscreensaver missing who staying in plasma4...Many thanks for your answer see you

So you want either Plasma 5 + screensavers or Plasma 4 (on a distro which still supports it)?

I don't know what the state of using screensavers with Plasma 5 currently is, or how to go about enabling it. Others on the forum might know.
As for using Plasma 4, your best bet is either to use an LTS distro which still supports it, like Kubuntu 14.04 or Debian Jessie. If you want to upgrade to a newer version of your distro which only provides Plasma 5, you're going to need to compile and install it manually.

Hello,
here is screen saver model on plasma4, not exist in plasma5... This is my question again, it's possible to renew the plasma4 in a OS 16.04 with plasma 5?
I would like change it plasma5 for return to plasma4? possible or not? many thanks

It should be possible to use XScreemSaver with Plasma5 and it's what I would recommend

https://wiki.archlinux.org/index.php/XScreenSaver

As I recall I followed this link to set Xscreensaver on my laptop with Plasma5.

Also, these steps are outlined in the xscreensaver man page. I followed as well the step for setting xscreensaver to be the locker and it works most of the time.