Good morning, jeff
Latest MX Linux is based on Debian 13, so you should instead install our repositories instead of the PPA ones, you can find our repositories here:

https://slimbook.com/en/blog/guides-2/post/add-the-slimbook-repositories-on-linux-71

Regards,

MX linux is sysv init OS. 

Here is the ouptut errror.

Setting up: slimbook-keyboard-dkms (0.2.9)
Removing:   old slimbook_keyboard/0.0 DKMS files
/usr/sbin/dkms.real remove -m slimbook_keyboard -v 0.0 --all
Deleting module slimbook_keyboard/0.0 completely from the DKMS tree.
Loading new slimbook_keyboard/0.0 DKMS files
/usr/sbin/dkms.real add -m slimbook_keyboard -v 0.0
Building for 6.12.63+deb13-amd64 and 6.12.74+deb13+1-amd64
Building for architecture x86_64
/usr/sbin/dkms.real status -m slimbook_keyboard -v 0.0 -k 6.12.63+deb13-amd64 -a x86_64
Building initial module slimbook_keyboard/0.0 for 6.12.63+deb13-amd64
/usr/sbin/dkms.real build -m slimbook_keyboard -v 0.0 -k 6.12.63+deb13-amd64 -a x86_64 -k  
6.12.74+deb13+1-amd64 -k 6.12.63+deb13-amd64 -a x86_64
Error! If more than one arch is specified on the command line, then there
must be an equal number of kernel versions also specified (1:1 relationship).
dpkg: error processing package slimbook-keyboard-dkms (--configure):
installed slimbook-keyboard-dkms package post-installation script subprocess returned error exit  
status 1
Setting up: slimbook-base-files (24.9.0)
Leaving 'diversion of /usr/share/pixmaps/ubuntu-logo-text.png to  
/usr/share/pixmaps/ubuntu-logo-text.png.distrib by slimbook-base-files'
cp: cannot stat '/usr/share/pixmaps/ubuntu-logo-text.png': No such file or directory
dpkg: error processing package slimbook-base-files (--configure):
installed slimbook-base-files package post-installation script subprocess returned error exit  
status 1
dpkg: dependency problems prevent configuration of slimbook-keyring:
slimbook-keyring depends on slimbook-base-files; however:
 Package slimbook-base-files is not configured yet.
dpkg: error processing package slimbook-keyring (--configure):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of slimbook-meta-elemental:
slimbook-meta-elemental depends on slimbook-keyboard-dkms; however:
 Package slimbook-keyboard-dkms is not configured yet.
dpkg: error processing package slimbook-meta-elemental (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
slimbook-keyboard-dkms
slimbook-base-files
slimbook-keyring
slimbook-meta-elemental
╭─────────────────────────────────────────────────────────────────────────────────────────────────╮
│⠹ Running dpkg … ━━━━━━╺━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 11.1% • -:--:-- • 1/9│
╰─────────────────────────────────────────────────────────────────────────────────────────────────╯
Error: Installation has failed.
If you'd like to file a bug report please include '/var/log/nala/dpkg-debug.log'

Error: error processing package slimbook-keyboard-dkms (--configure):

Error: error processing package slimbook-keyboard-dkms (--configure):
installed slimbook-keyboard-dkms package post-installation script subprocess returned error exit s
tatus 1
installed slimbook-keyboard-dkms package post-installation script subprocess returned error exit s
tatus 1
Setting up slimbook-base-files (24.9.0) ...
Setting up slimbook-base-files (24.9.0) ...
cp: cannot stat '/usr/share/pixmaps/ubuntu-logo-text.png': No such file or directory
cp: cannot stat '/usr/share/pixmaps/ubuntu-logo-text.png': No such file or directory

Error: error processing package slimbook-base-files (--configure):

Error: error processing package slimbook-base-files (--configure):
installed slimbook-base-files package post-installation script subprocess returned error exit stat
us 1
installed slimbook-base-files package post-installation script subprocess returned error exit stat
us 1

Error: dependency problems prevent configuration of slimbook-keyring:

Error: dependency problems prevent configuration of slimbook-keyring:
slimbook-keyring depends on slimbook-base-files; however:
slimbook-keyring depends on slimbook-base-files; however:
 Package slimbook-base-files is not configured yet.
 Package slimbook-base-files is not configured yet.

Error: error processing package slimbook-keyring (--configure):

Error: error processing package slimbook-keyring (--configure):
dependency problems - leaving unconfigured
dependency problems - leaving unconfigured

Error: dependency problems prevent configuration of slimbook-meta-elemental:

Error: dependency problems prevent configuration of slimbook-meta-elemental:
slimbook-meta-elemental depends on slimbook-keyboard-dkms; however:
slimbook-meta-elemental depends on slimbook-keyboard-dkms; however:
 Package slimbook-keyboard-dkms is not configured yet.
 Package slimbook-keyboard-dkms is not configured yet.

Error: error processing package slimbook-meta-elemental (--configure):

Error: error processing package slimbook-meta-elemental (--configure):
dependency problems - leaving unconfigured
dependency problems - leaving unconfigured

Errors were encountered while processing:
slimbook-keyboard-dkms
slimbook-base-files
slimbook-keyring
slimbook-meta-elemental
[08:35:51] jeff@mx /home/jeff [1]  
>

Hello, Jeff
If SysVInit is compatible with udev, it shouldn't be a problem, some applications that we offer need udev for functioning properly
As udev itself can be installed without installing all of the systemd, other distros that do not use systemd are compatible with our applications
I suggest reinstalling these packages if you already installed before and gave an error setting up, then using our repositories instead of the PPA (and remove the PPA!)

We have tested an installation of MxLinux here and it should install properly 

Regards,

I have udev installed.

Here is the output from the command
 7:52:47] jeff@mx /home/jeff   
> slimbookrgbkeyboard
Slimbook Essential/Elemental/Hero-S detected
Traceback (most recent call last):
 File "/usr/bin/slimbookrgbkeyboard", line 21, in <module>
   slimbookrgbkeyboard.main()
   ~~~~~~~~~~~~~~~~~~~~~~~~^^
 File "/usr/share/slimbookrgbkeyboard/src/slimbookrgbkeyboard.py", line 177, in main
   win = SlimbookRGBKeyboard()
 File "/usr/share/slimbookrgbkeyboard/src/slimbookrgbkeyboard.py", line 66, in __init__
   self.load_main_grid(win_grid)
   ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
 File "/usr/share/slimbookrgbkeyboard/src/slimbookrgbkeyboard.py", line 126, in load_main_grid
   win_grid.attach(libslimbook_backlight.Grid(), 0, 1, 5, 5)
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~^^
 File "/usr/share/slimbookrgbkeyboard/src/libslimbook_backlight.py", line 26, in __init__
   self.read_backlight()
   ~~~~~~~~~~~~~~~~~~~^^
 File "/usr/share/slimbookrgbkeyboard/src/libslimbook_backlight.py", line 172, in read_backlight
   color = int(output,16)
ValueError: invalid literal for int() with base 16: 'Failed to retrieve keyboard backlight:5'
[17:52:58] jeff@mx /home/jeff [1]  
>  

Hello, Jeff
Make sure you have the kernel driver package both installed and loaded, you'd need to install the kernel headers of your current kernel to load the driver correctly
You can check with `slimbookctl info` if your driver designated for this device is loaded or not

Regards,

Where is the slimbookctl info located?

Hello, Jeff
It is a command. After installing the slimbook packages (slimbook-meta-common installs this), it should be available in the system and you can execute it in the terminal

Regards,