There is a hidden site setting to allow admins to include S3 uploads in the backups. To enable it, you’d set the SiteSetting at the Rails console like below
cd /var/discourse
./launcher enter app
rails c
SiteSetting.include_s3_uploads_in_backups=true
exit
exit
This change takes effect immediately. No further action is necessary.
Another way to accomplish this would be to add it to app.yml file in the env: section. To do that you would add it in the env: section (say, under DISCOURSE_HOSTNAME)
DISCOURSE_INCLUDE_S3_UPLOADS_IN_BACKUPS: true
To have this change take effect, you need to run ./launcher rebuild app command to have that setting applied.
I’m certain you need to destroy and start to change the env variables applied to the container.
Of course, if they have done upgrades with docker manager, those will be lost when the container is destroyed, which is why the rebuild is the safest recommendation. Maybe it’s best to recommend the rebuild since it’s the most foolproof.