This script allows you to setup Cosmovisor inside your Desmos node so that it will be able to automatically upgrade itself for the Desmos September Upgrade

desmos-cosmovisor-installer.sh

#!/usr/bin/env bash

# This script allows the easy installation of the Cosmovisor daemon to watch
# any upgrade of your Desmos node.
# In order to run it properly, just execute this script giving it the path
# to the folder where you cloned Desmos.
# Example:
# ./install-cosmovisor.sh ~/desmos

DESMOS_PATH=$1
if [ -z "$DESMOS_PATH" ]; then
  echo "Invalid Desmos code path. Please provide it as the first argument"
  exit
fi

USER=$(id -u -n)

# Setup GOBIN if not existent
if [ -z "$GOBIN" ]; then
  echo "export GOBIN=$HOME/go/bin" >> ~/.profile
  source ~/.profile
fi

############################
## 1. Install cosmovisor ##
############################

echo "===> Installing cosmovisor <==="
mkdir -p ~/cosmos
cd ~/cosmos
git clone https://github.com/cosmos/cosmos-sdk.git .
cd cosmovisor
make cosmovisor
cp cosmovisor $GOBIN/cosmovisor

#########################
## 2. Setup cosmovisor ##
#########################

echo "===> Setting up cosmovisor <==="
mkdir -p ~/.desmosd/cosmovisor
mkdir -p ~/.desmosd/cosmovisor/genesis/bin
mkdir -p ~/.desmosd/cosmovisor/upgrades
cp $GOBIN/desmosd ~/.desmosd/cosmovisor/genesis/bin

if [ -z "$DAEMON_NAME" ]; then
  echo " " >> ~/.profile
  echo "# Setup Cosmovisor" >> ~/.profile
  echo "export DAEMON_NAME=desmosd" >> ~/.profile
  echo "export DAEMON_HOME=$HOME/.desmosd" >> ~/.profile
  echo "export DAEMON_RESTART_AFTER_UPGRADE=on" >> ~/.profile
  source ~/.profile
fi


######################
## 2. Setup upgrade ##
######################

echo "===> Setting up september upgrade <==="
mkdir -p ~/.desmosd/cosmovisor/upgrades/september-upgrade/bin
cd $DESMOS_PATH
git fetch -a && git checkout tags/v0.12.1
make build
cp build/desmosd ~/.desmosd/cosmovisor/upgrades/september-upgrade/bin

######################
## 3. Setup service ##
######################

FILE=/etc/systemd/system/desmosd.service
if test -f "$FILE"; then
  sudo tee $FILE > /dev/null <<EOF
[Unit]
Description=Desmosd Full Node
After=network-online.target

[Service]
User=$USER
ExecStart=$GOBIN/cosmovisor start
Restart=always
RestartSec=3
LimitNOFILE=4096
Environment="DAEMON_NAME=desmosd"
Environment="DAEMON_HOME=$HOME/.desmosd"
Environment="DAEMON_RESTART_AFTER_UPGRADE=ony"

[Install]
WantedBy=multi-user.target
EOF

  echo "===> Restarting service <==="
  sudo systemctl stop desmosd
  sudo systemctl daemon-reload
  sudo systemctl start desmosd
fi

echo "===> Completed setup <==="

[Service]
User=$(id -u -n)
ExecStart=/home/$(id -u -n)/go/bin/cosmovisor start
Restart=always
RestartSec=3
LimitNOFILE=4096
Environment="DAEMON_NAME=desmosd"
Environment="DAEMON_HOME=$HOME/.desmosd"
Environment="DAEMON_RESTART_AFTER_UPGRADE=ony"

Thank you very much @novy4! We've updated the script to include your suggestion