Admin theme gone

[olavt]

I upgraded to 1.12. But as with previous upgrades, the admin theme is gone. I only get an unformatted admin page (list), which is more that just a bit frustrarting. I have noticed that there are new admin themes to install, and would like to see how itworks if I install one. But there are no instructions on how to install them (or at least: I have not found them).

[Jo Morg]

I upgraded to 1.12.

From which version?

But as with previous upgrades, the admin theme is gone.

Which theme were you using?

I have noticed that there are new admin themes to install, and would like to see how itworks if I install one. But there are no instructions on how to install them (or at least: I have not found them).

There is a folder called themes in <cmsms root>/admin/ where you can upload the admin themes, keeping of course the folder structure of each theme separate (as it originally is on the 2 themes provided).
I don't know if any of the 3r party themes are currently compatible with 1.12, but I have never experienced what you describe in the numerous sites I have upgraded during all these years, which tells me that probably your server settings are not correctly set, or don't meet the minimum requirements for CMSMS plus the 3rd party modules you may have installed. The other possible reason is that you may have installed old 3rd party modules that are not up to date with the current CMSMS version, but is impossible to tell from the lack of information on your post....