Is changing plymouth-theme different in 16.04?

I have some plymouth themes on the path /usr/share/plymouth/themes.

But I cannot set them. I first tried sudo update-alternatives --config default.plymouth then chose the theme. after that sudo update-initramfs -u

There were no errors. But it's not working. Plymouth-manager is not working too (installed but not running). I use Ubuntu 16.04 amd64