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

Here's my spin on it, not completely tested so be careful:

#!/bin/bash
# Script should be run with this command: sudo bash UpdateTeku.sh
echo Go here: https://github.com/ConsenSys/teku/releases and copy the tar.gz link, then paste it into here
read UpdateFilePath
echo From the same page, copy the sha256 hash for the tar.gz file
read Sha256Hash
UpdateFileName="${UpdateFilePath##*/}"
UpdateVersion=${UpdateFileName::-7}
echo "File name is: $UpdateFileName"
echo "Update version is: $UpdateVersion"
# Remove existing contents of temporary Teku directory (if any, probably not)
sudo rm -rf /var/lib/teku/tmp/*
# Download the new version and do a checksum check. Output check is manual
TEKU_VERSION="$UpdateFileName"; curl -s "$UpdateFilePath" -o "$UpdateFileName" && shasum -a 256 -c <<< "$Sha256Hash *$TEKU_VERSION" || (echo "Checksum failed deleting f>
# Stop the Teku client service
sudo systemctl stop teku
# Remove old Teku files
sudo rm -r /usr/local/bin/teku
# Copy in new files
sudo cp -a "/var/lib/teku/tmp/$UpdateVersion/." /usr/local/bin/teku/
# Start the Teku client service
sudo systemctl start teku
# Remove existing contents of temporary Teku directory (don't really need to do this since it gets done earlier in the script, I just want to keep things clean)
sudo rm -rf /var/lib/teku/tmp/*
# TODO: remove the downloaded .tar.gz file
# Check for errors
sudo systemctl status teku
# Monitor
sudo journalctl -fu teku.service

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