K> Does anyone know where I can find GnuPG 2.0.16 for CentOS 6.9 32-bit?

Do you want something that old? 2.0.17 came out in 2011. I run
Oracle Linux 6.9 (basically RHEL without the trademarks) — if you’re
comfortable building from source, GnuPG-2.2.5 wasn’t hard. This is
what I did:

Download files:

site=’https://gnupg.org/ftp/gcrypt’

curl $site/libassuan/libassuan-2.5.1.tar.bz2
curl $site/libassuan/libassuan-2.5.1.tar.bz2.sig
curl $site/libgcrypt/libgcrypt-1.8.2.tar.bz2
curl $site/libgcrypt/libgcrypt-1.8.2.tar.bz2.sig
curl $site/libgpg-error/libgpg-error-1.28.tar.bz2
curl $site/libgpg-error/libgpg-error-1.28.tar.bz2.sig
curl $site/libksba/libksba-1.3.5.tar.bz2
curl $site/libksba/libksba-1.3.5.tar.bz2.sig
curl $site/npth/npth-1.5.tar.bz2
curl $site/npth/npth-1.5.tar.bz2.sig
curl $site/gnupg/gnupg-2.2.5.tar.bz2
curl $site/gnupg/gnupg-2.2.5.tar.bz2.sig

Check the tarballs against GPG signatures and unpack.

Build libraries first:

export CC=gcc
export CXX=g++
export CFLAGS=-O2
export LDFLAGS=”-L/usr/local/lib”
export CPPFLAGS=”-I/usr/local/include”
dest=/usr/local

cd /path/to/libassuan-source
./configure –prefix=$dest –mandir=$dest/man
make && make check && make install && make clean

cd /path/to/libgcrypt-source
./configure –prefix=$dest –mandir=$dest/man
make && make check && make install && make clean

cd /path/to/libgpg-error-source
./configure –prefix=$dest –mandir=$dest/man
make && make check && make install && make clean

cd /path/to/libksba-source
./configure –prefix=$dest –mandir=$dest/man
make && make check && make install && make clean

cd /path/to/npth-source
./configure –prefix=$dest –mandir=$dest/man
make && make check && make install && make clean

Build gnupg — this was more interesting because I needed the realtime
library (librt) as well as a local ncurses library (libncursesw)
to make readline stuff work. You may not need this, depending on
how your libraries are set up:

export CC=gcc
export CXX=g++
export CFLAGS=-O2
export LDFLAGS=”-L/usr/local/lib -L/usr/lib64″
export LIBS=”-lreadline -lncursesw -lrt”
export CPPFLAGS=”-I/usr/local/include”
dest=/usr/local

cd /path/to/gnupg-source
./configure –prefix=$dest –mandir=$dest/man

[change config.h to hold “#undef HAVE_INOTIFY_INIT” unless
you have a very recent release of inotify sources]

make && make check && make install && make clean

It’s a little tedious but it works.