Gfilui

I wonder what

"$distro_idESM:$distro_codename";

is in the 50unattended-upgrades file. It was enabled by default for me (after enabeling unattended-upgrades package at least.) Right now I disabled it and only have -security enabled for automatic upgrades but I would like to understand what it is and whether it would be good to uncomment that line again.

Here is the block it's in;

Unattended-Upgrade::Allowed-Origins // 
"$distro_id:$distro_codename";
 "$distro_id:$distro_codename-security"; 
 // Extended Security Maintenance; doesn't necessarily exist for 
 // every release and this system may not have it installed, but if 
 // available, the policy for updates is such that unattended-upgrades 
 // should also install from here by default. 
 // "$distro_idESM:$distro_codename"; 
// "$distro_id:$distro_codename-updates"; 
// "$distro_id:$distro_codename-proposed"; 
// "$distro_id:$distro_codename-backports"; 
;

Is it some sort of mother that should be enabled before I can enable the -updates, -proposed, -backports?

Thanks a lot.

It's Canonical's Extended Security Maintenance for LTS releases after normal release end-of-life. At the moment, unless you're using 12.04 and paying for it, it doesn't apply to you.