about system does not work

[leszek]

Enabling testing-neon and testing repos should be enough. After a package refresh

Code:

sudo apt-get update

you can start the update process with

Code:

sudo apt-get dist-upgrade

.
The kcm-about-extended has to be upgraded manually like described above.

That should be it.

As for the plasmashell delay. Do you have any autostart applications or session restore turned on?
Have you tried maybe with a new user?
My testing machine shows no significant loading time changes.