cryptsetup: /lib/arm-linux-gnueabihf/libcryptsetup.so.12: version `CRYPTSETUP_2.4' not found error

Hi all,

I had to reinstall the OS on an old raspberry pi. (The new OS is Raspberry PI 32 bit OS, most recent version.)

I have installed cryptsetup-2.4.3 as described here: https://www.linuxfromscratch.org/blfs/view/svn/postlfs/cryptsetup.html. (It needed a bunch of dependencies which were also installed.)

Now when I try

$ sudo cryptsetup luksOpen /dev/sda1 backup

which is how it used to work, I get the error in the subject:

cryptsetup: /lib/arm-linux-gnueabihf/libcryptsetup.so.12: version `CRYPTSETUP_2.4' not found (required by cryptsetup)

apt claims that I have the newest version, v2.3.7:

$ apt search libcryptsetup
Sorting... Done
Full Text Search... Done
libcryptsetup-dev/stable,now 2:2.3.7-1+deb11u1 armhf [installed]
disk encryption support - development files

libcryptsetup12/stable,now 2:2.3.7-1+deb11u1 armhf [installed]
disk encryption support - shared library

What am I missing? Thanks for any help.
Geza