Xenforo takes that from PHP's compiled OpenSSL version which is default CentOS 7 system version OpenSSL 1.0.2k. If you're using my Centmin Mod LEMP stack, only Nginx gets it's own OpenSSL 1.1.1m build used for Nginx alone. So how did you upgrade system to OpenSSL 1.1.1m? As Centmin Mod doesn't upgrade system OpenSSL as it can break other software.
Centmin Mod Nginx build
nginx -V
nginx version: nginx/1.21.6 (270122-045016-centos7-kvm-b5dac64-br-9aec15e)
built by gcc 10.2.1 20210130 (Red Hat 10.2.1-11) (GCC)
built with OpenSSL 1.1.1m 14 Dec 2021
TLS SNI support enabled
nginx version: nginx/1.21.6 (270222-174515-centos7-kvm-11242b2)
built by gcc 10.2.1 20210130 (Red Hat 10.2.1-11) (GCC)
built with OpenSSL 1.1.1m 14 Dec 2021
TLS SNI support enabled
/opt/openssl/bin/openssl version
[CODE version
OpenSSL 1.1.1m 14 Dec 2021[/CODE]
wget https://ftp.openssl.org/source/openssl-1.1.1m.tar.gz
tar -xzvf openssl-1.1.1m.tar.gz
cd openssl-1.1.1m
./config --prefix=/usr --openssldir=/etc/ssl --libdir=lib no-shared zlib-dynamic
make
make test
make install