Compile gnupg 2.4.x from Source for Debian Testing

compile_gnupg.sh

# assumes new Debian Testing VM, for purpose of compiling, running below as root
# uses most libs already available from apt, only compiles lib ntbtls

lsb_release -a
uname -a

wget https://gnupg.org/signature_key.asc
gpg --import signature_key.asc
gpg -k
wget https://www.gnupg.org/signature_key.html
cat signature_key.html | grep -A 1 ed25519
# verify fingerprints

wget https://www.gnupg.org/ftp/gcrypt/ntbtls/ntbtls-0.3.1.tar.bz2
wget https://www.gnupg.org/ftp/gcrypt/ntbtls/ntbtls-0.3.1.tar.bz2.sig
wget https://www.gnupg.org/ftp/gcrypt/gnupg/gnupg-2.4.3.tar.bz2
wget https://www.gnupg.org/ftp/gcrypt/gnupg/gnupg-2.4.3.tar.bz2.sig

gpg --verify ntbtls-0.3.1.tar.bz2.sig
gpg --verify gnupg-2.4.3.tar.bz2.sig
# verify sigs

apt -y remove gpg-agent

apt update
apt -y upgrade
apt -y install curl zip unzip bzip2 gettext texinfo gnutls-bin libgnutls28-dev build-essential checkinstall libbz2-dev zlib1g-dev libsqlite3-dev libldap-dev dirmngr pinentry-curses libassuan0 libassuan-dev libksba8 libksba-dev libnpth0 libnpth0-dev libncurses-dev libncurses6 libgpgme11 libgpgme-dev libgpg-error0 libgpg-error-dev gpgrt-tools libgcrypt20 libgcrypt20-dev
apt -y autoremove

bunzip2 ntbtls-0.3.1.tar.bz2
tar xvf ntbtls-0.3.1.tar
bunzip2 gnupg-2.4.3.tar.bz2
tar xvf gnupg-2.4.3.tar

cd ntbtls-0.3.1 && ./configure && make && make install && cd ..
cd gnupg-2.4.3 && ./configure && make && make install && cd ..
echo "/usr/local/lib" > /etc/ld.so.conf.d/gpg2.conf
gpgconf --kill all
gpg -K
gpg --version

# reboot & done