The Debian GNU/Linux project has released an updated version of its stable Linux distribution Debian 9 (“stretch”). This is the final update in the 9.x version. You must upgrade to get corrections for security problems as this version made a few adjustments for the severe issue found in Debian version 9.12. Debian is a Unix-like (Linux distro) operating system and a distribution of Free Software. It is mainly maintained and updated through the work of many users who volunteer their time and effort. The Debian Project was first announced in 1993 by Ian Murdock.
apt-get command/apt command to upgrade your system:
$ sudo apt-get update
$ sudo apt-get dist-upgrade
Make sure finally reboot the Linux system to get updated kernel and other libs:
$ sudo reboot
Verify that upgrade went smoothly with help of cat command/grep command/egrep command:
$ uname -mrs
$ lsb_release -a
$ dmesg | egrep -i 'err|warn|critical'
$ sudo tail -f /var/log/myapp
The Debian Linux 9 installer updated to include the fixes incorporated into stable by the point release. You can download updated ISO for full installation too. This stable update added important package corrections and security enhancements to the system. Since this is the final release in Debian GNU/Linux 9.xx series, I strongly suggest that you upgrade to the Debian Linux 10 ASAP. Happy upgrades!