If you are updating to Unomaly 3.3.4 and the installation fails with the following message:
Failed to execute operation: No such file or directory
Please run the following commands:
sudo rm /etc/systemd/system/redis.service
sudo rm /DATA/unomaly_UPGRADING
Then re-run the upgrade as usual.
Note that this should not happen if your installation was originally done after 2017. If that is the case or if you still encounter errors after this procedure, please contact support.