The preferred method to do this is using the command plymouth-set-default-theme.
If you enter this command, without parameters, as user root you’ll see something like
This lists the themes installed on your computer. The default is ‘charge’. If you want to see the boot up details you used to see in version 6, try
Followed by the command
This process modifies the boot loader so you won’t have to update your grub.conf file manually every time for each new kernel update.