Using a compiled from source library that is a newer version of a preexisting library - linux

Question

I'm unsure about some small obscure details that I worry will have large effects. On my Raspbian Debian 11 running on a Raspberry Pi, sudo apt update && sudo apt full-upgrade only updates my libxml2 library to version 2.9.10, no further. However, I need version 2.9.14 for the security patches contained within. With help from this question (thank you Esther!), I decided to compile version 2.9.14 from source. Everything went well, and the library was placed into /usr/local/lib. I then updated ldconfig by following this answer. However, although that should have made Debian use the new 2.9.14 version, apt-cache policy libxml2 still shows:
libxml2:
Installed: 2.9.10+dfsg-6.7+deb11u2
Candidate: 2.9.10+dfsg-6.7+deb11u2
Version table:
*** 2.9.10+dfsg-6.7+deb11u2 500
500 http://raspbian.raspberrypi.org/raspbian stable/main armhf Packages
100 /var/lib/dpkg/status
I think I know why this is. If I was installing a never-before-seen library, everything might have worked properly. However, since I now have a second libxml2 library without removing the 1st, any time the system needs to use libxml2, the search first reaches /usr/lib/arm-linux-gnueabihf where the old libxml2 is, so the system finds the old version, is satisfied, and so stops searching before finding the new version.
For context before I continue:
(link to below but in color: https://i.stack.imgur.com/OJLJW.png)
pi#fuelightcontrol:~ $ cd /usr/lib/arm-linux-gnueabihf/
pi#fuelightcontrol:/usr/lib/arm-linux-gnueabihf $ ls -l | grep libxml2
lrwxrwxrwx 1 root root 17 May 15 14:58 libxml2.so.2 -> libxml2.so.2.9.10
-rw-r--r-- 1 root root 1510312 May 15 14:58 libxml2.so.2.9.10
pi#fuelightcontrol:/usr/lib/arm-linux-gnueabihf $ cd /usr/local/lib
pi#fuelightcontrol:/usr/local/lib $ ls -l
total 12120
drwxr-xr-x 3 root root 4096 Jun 14 18:17 cmake
-rw-r--r-- 1 root root 7145994 Jun 14 18:17 libxml2.a
-rwxr-xr-x 1 root root 944 Jun 14 18:17 libxml2.la
lrwxrwxrwx 1 root root 17 Jun 14 18:17 libxml2.so -> libxml2.so.2.9.14
lrwxrwxrwx 1 root root 17 Jun 14 18:17 libxml2.so.2 -> libxml2.so.2.9.14
-rwxr-xr-x 1 root root 5242072 Jun 14 18:17 libxml2.so.2.9.14
drwxr-xr-x 2 root root 4096 Jun 14 18:17 pkgconfig
drwxr-xr-x 3 root root 4096 Jun 13 21:43 python3.9
-rw-r--r-- 1 root root 205 Jun 14 18:17 xml2Conf.sh
pi#fuelightcontrol:/usr/local/lib $
The question is, what would be the best way to go about fixing the problem of the old version still being used by apt-cache policy libxml2 and other programs? I could:
Just delete /usr/lib/arm-linux-gnueabihf/libxml2.so.2.9.10 (the old one) and its symbolic link, so the system keeps searching past that point and eventually finds /usr/local/lib/libxml2.so.2.9.14 (the new one). However, something feels... off about having my libraries scattered around in different directories. My gut tells me to keep them in one place. Also, see paragraph below the next list item.
I could delete /usr/lib/arm-linux-gnueabihf/libxml2.so.2.9.10 (the old one) and its symbolic link, then move the new version into /usr/lib/arm-linux-gnueabihf to replace the old version. However, there's more libxml2 related files and 1 more symbolic link in /usr/local/lib that are not present in /usr/lib/arm-linux-gnueabihf. Do I need to move those too, or should I just move libxml2.so.2.9.14 and one (both?) of the symbolic links? If only 1 link, which?
Should I delete the files left behind after I move the required ones over? Also, see paragraph below.
What concerns me about deleting anything is if some other script comes looking for libxml2.2.9.10, can't find it, and fails. I don't know how to tell the rest of the programs that libxml2's filename is different now. I suppose both options 1 and 2 might work, but is one option a cleaner, smarter idea? I'm trying to save myself some work in the future.
Sorry this is such a small silly question. Thank you for your help!
Edit: After making backups of both directories, I tried option 1 first, then option 2. Neither changed the output of apt-cache policy libxml2 - it still says I have libxml2 2.9.10 installed, even though I deleted /usr/lib/arm-linux-gnueabihf/libxml2.so.2.9.10 and its symbolic link, rebooted, and ran sudo apt update
Here's how I updated ldconfig (same as the second link), to clear up loose ends. The link to /usr/local/lib was done for me already, which was nice.
Link to screenshot of below but in color: https://i.stack.imgur.com/7w6XR.png
pi#fuelightcontrol:/etc $ ls -l ld.so.conf
ld.so.conf ld.so.conf.d/
pi#fuelightcontrol:/etc $ cat ld.so.conf
include /etc/ld.so.conf.d/*.conf
pi#fuelightcontrol:/etc $ ls -l ld.so.conf.d
total 16
-rw-r--r-- 1 root root 12 Dec 1 2021 00-vmcs.conf
-rw-r--r-- 1 root root 109 May 14 2019 arm-linux-gnueabihf.conf
-rw-r--r-- 1 root root 41 Jun 25 2018 fakeroot-arm-linux-gnueabihf.conf
-rw-r--r-- 1 root root 44 Jun 14 19:08 libc.conf
pi#fuelightcontrol:/etc $ cat ld.so.conf.d/libc.conf
# libc default configuration
/usr/local/lib
pi#fuelightcontrol:/etc $ sudo ldconfig
pi#fuelightcontrol:/etc $ sudo ldconfig /usr/local/lib
pi#fuelightcontrol:/etc $ sudo ldconfig -n /usr/local/lib
pi#fuelightcontrol:/etc $ cat ld.so.conf.d/00-vmcs.conf
/opt/vc/lib
pi#fuelightcontrol:/etc $ cat ld.so.conf.d/arm-linux-gnueabihf.conf clear
# Multiarch support
/usr/local/lib/arm-linux-gnueabihf
/lib/arm-linux-gnueabihf
/usr/lib/arm-linux-gnueabihf
cat: clear: No such file or directory
pi#fuelightcontrol:/etc $ cat ld.so.conf.d/fakeroot-arm-linux-gnueabihf.conf
/usr/lib/arm-linux-gnueabihf/libfakeroot
pi#fuelightcontrol:/etc $