...from Ubuntu Server 24.04.5 LTS to 26.04.1 LTS.

Also...
* PHP 5.6.40 and 7.4.33 had to be community-patched in order to compile at all for the 26.04 environment
  - PHP 7.4.33 is properly patched for gcc/g++/cpp 15, but PHP 5.6.40 was very hack-patched by me in order for it to compile with 15 (I would not trust that, lol - also I used some errors-to-warnings flags as well...)
* PHP 5.6.40 is barely used on the server, only two or three vintage projects use it at all
* PHP 7.4.33 is still set globally for projects
* PHP 8.5.11 and PHP 8.6.0RC2 needed to be recompiled
* All C-adjacent compilers were to be changed back to gcc/g++/cpp 13 from 15 - far into the future, I would use 15
  - Also found out that early major PHP 8 versions without modifications fail to compile; I think PHP 8.4 may be the earliest version that compiles with gcc/g++/cpp 15
* libicu/icu4c needed to be source-compiled because the system version was built against gcc/g++/cpp 15, and the environment uses 13
* Apache httpd and Apache apr-util were updated (security)