Getting errors while installing etherlab master

E: Unable to locate package linux-headers-4.19.71-rt24-v7l
E: Couldn't find any package by glob 'linux-headers-4.19.71-rt24-v7l'
E: Couldn't find any package by regex 'linux-headers-4.19.71-rt24-v7l'

I want to install etherlab master on raspberry pi while installing get above errors please provide any solutions for Above errors
 

Way out of date
Install linuxcnc 2.9 from the official ISO and install ethercat from the provided and installed repositories. Refer to the sticky in the ethercat section

Thanks for the reply !!

I did sudo apt update and upgrade.

Hi Rod, I was hoping for your reply since I followed your steps for installing Ethercat. I have successfully installed and able to detect slaves as well.

Also I have created udev rule so that I don't have to give permission everytime, but everytime I reboot or start rpi4 "/dev/EtherCAT0" vanishes !!

I have found solution from the last post of "Ethercat installation from repositories":
root@raspberrypi:~# /usr/sbin/ethercatctl stop
rmmod: ERROR: Module ec_master is in use by: ec_genet
root@raspberrypi:~# rmmod ec_genet
root@raspberrypi:~# /usr/sbin/ethercatctl stop
root@raspberrypi:~# /usr/sbin/ethercatctl start

After following this commands I am able to see "/dev/EtherCAT0", can you please help me with this so that I don't have to follow above commands?

Thanks !!

I suspect you missed setting upa udev rule as outlined in the instructions

Nope, I have followed these three steps:

Did I miss something?

Thanks !!