...It's an overbuilt machine running on two AMD Opteron Dual-Core CPUs, but the system memory capacity is pretty lacking (~4.75GB of RAM) because multiple 1GB ECC Registered DDR sticks were dying over time... otherwise it would be running on 6GB of ECC RAM.
That system can theoretically run on 24GB of RAM, but that is 4GB per DDR stick, and... nah. Expensive, even back then, so 2GB per stick may be more reasonable.
It was a misconfiguration regarding limiting IP connections on the server. It was from a modification some few months ago (probably back in the summer) when the top-level directory was meant to be limited... but it was too limited. This affected most of the website, lol.
... yeah, that was chaotic. Back-end has four versions of the same cURL library version , and that is because it uses different openSSL major releases.
From there, there are four PHP versions, each using those different versions.
Apache httpd is still using openssl 1.1.1, however.
New
libicu/icu4c: 74.2, 78.3 - compiled using gcc/g++ 13 compiler
Recompile
php 5.6.40: due to system upgrade
php 7.4.33: due to system upgrade, needed libicu 74.2 so PHP is not forced to use c++17 standards for compiling (with c++17 flag you can use later libicu versions)
php 8.5.11, 8.6.0RC2: due to system upgrade, initial gcc/g++ 15 to final gcc/g++13 migration, and changing from system-built libicu-78.2 compiled with gcc/g++ 15 to source-built libicu-78.3 compiled with gcc/g++ 13
Very little actually runs on PHP 5.6, but this microblog runs on PHP 7.4... and it breaks on PHP 8.x.
My laptop runs Kubuntu 26.04, but it's pretty hacky. I patched PHP 5.6.40 and PHP 7.4.33 and they do compile on my laptop, and will try again on the compile box later.
This server is still running Ubuntu Server 24.04 until it is ensured that earlier PHP can run. As a note, PHP 8.5 and PHP 8.6 can actually compile without issue.