How I upgrade Teku on my Ethereum Validator

manually_update_teku.sh

# Warning: This is a human script that needs to be used interatively.
#          That said it wouldn't take much to improve it so it could all be done with a single invocation

# Download the new version and do a checksum check. Output check is manual
TEKU_VERSION="teku-21.2.0.tar.gz"; curl -s https://artifacts.consensys.net/public/teku/raw/names/teku.tar.gz/versions/21.2.0/$TEKU_VERSION -o $TEKU_VERSION && shasum -a 256 -c <<< "27aba84f4ac8678ebd7dea7d2e19790cad7d04b5faf9108ce331c2f8a9e2330f *$TEKU_VERSION" || (echo "Checksum failed deleting file" && rm $TEKU_VERSION); tar -xf $TEKU_VERSION -C /opt

# Create a symlink to the newly extracted teku version
ln -s /opt/teku-21.2.0/bin/teku /usr/bin/teku-21.2.0

# Edit the service file to point to the new symlink
vim /etc/systemd/system/teku.service

# Restart everything and watch the validator start
systemctl daemon-reload
systemctl restart teku && journalctl -u teku -f

Now tested and confirmed working, at least on my machine.