There are community backports (like Sury’s Debian builds) for PHP, including a branch of PHP 5.6 originally released in 2014. Most other notable languages and major packages have something likewise as well, right down to major packages like Drupal 6. It’s not always easy, but it’s doable and the work is usually either already done or can be paid for.
Weird things that are truly too difficult to support are also often excluded. Eg Spectre/Meltdown fixes were non-trivial and had to be backported to a fairly wide range of things but that only went so far back. Some old systems just never got those fixes and instead have to be ran with a workaround (“don’t run untrusted code”). I don’t know how things are with the new offering but large complicated packages with lots of moving parts like OpenStack used to be excluded from the full extended support cycle before as well.
There are community backports (like Sury’s Debian builds) for PHP, including a branch of PHP 5.6 originally released in 2014. Most other notable languages and major packages have something likewise as well, right down to major packages like Drupal 6. It’s not always easy, but it’s doable and the work is usually either already done or can be paid for.
Weird things that are truly too difficult to support are also often excluded. Eg Spectre/Meltdown fixes were non-trivial and had to be backported to a fairly wide range of things but that only went so far back. Some old systems just never got those fixes and instead have to be ran with a workaround (“don’t run untrusted code”). I don’t know how things are with the new offering but large complicated packages with lots of moving parts like OpenStack used to be excluded from the full extended support cycle before as well.