Hi, a few days ago I changed my version of Discourse from 3.1.0.beta4 to 3.0.3 due to theme installation issues.
Now when I send a message in chat I get this error:
ERROR: relation “chat_uploads” does not exist LINE 1: SELECT “uploads”. FROM “uploads” INNER JOIN “chat_uploads” …* ^
The website link is: https://oii.francescomancuso.it/forum/
How can I fix it? Thank you
quick question, the forum is from discouse right?
Yes, is configured to run on the /forum/ subfolder
I’m afraid it’s not possible to downgrade.
Hi, thanks for the reply.
I didn’t downgrade exactly, I changed the version from beta to stable
Unfortunately that is a downgrade. Changing from the beta or tests-passed [1] branches down to stable is not possible as there will be differences in your database that aren’t backwards compatible.
the default one ↩︎
Ok, thanks a lot for the reply
So should I switch to the beta version to fix the problem?
Or wait for the stable version?
Thanks for your help 
A new Stable version is released about twice a year, so if you can hang on a couple of months you can wait for the next Stable version to be released. 
I’m not 100% sure if that will automagically make everything good again as it might be a spikey update considering you have 3.1.0beta4 rather than 3.0.3 Stable, but I think it might be okay. 
Or you can go back to using tests-passed in your app.yml and have an up-to-date version which should sort everything out. Just to check, is this a standard install?
Hi, thanks for the reply.
Yes it is, but I followed a guide here on the forum to make Discourse accessible via the /forum/ subfolder
Initially I had installed 3.1.0.beta4 but when I installed “Air Theme” or any other theme the site didn’t load the CSS stylesheets and the layout broke. 
After upgrading from beta to stable the theme didn’t conflict, but I lost some features 
Ah yes, you did say earlier on. The subfolder setup is an advanced one, and is not for the fainthearted. If you want an easy life you should consider the regular subdomain version.
Hi, thanks for your reply.
It is a temporary solution while waiting to buy a new domain
Also, following the steps seems to be working fine, including other sites installed on the server using nginx
You can’t use a subdomain? I’d argue that’s less confusing for users usually, e.g.:
community.acme.com
Hi, thanks for the reply. 
Actually for this project I’m already using a subdomain: https://oii.francescomancuso.it/
This includes a python application divided into 3 sections:
/admin/
/contest/
/ranking/
The user who logs in in the /contest/ section can connect via SSO to the forum, which is located in /forum/
Could the fact that the site is reachable from a subfolder cause me compatibility problems, for example with the theme using the beta version?
Thank you
There are no guarantees of compatibility with anything when using subfolder. It’s an advanced installation and very little is tested against it.
You could use a different subdomain for your discourse installation. SSO will work between subdomains.
The top of the subfolder guide contains this text:
You need to move back to tests-passed to be in a remotely supportable state, assuming your database isn’t just broken now. Rolling back a version is wholly unsupported.
Hi, thanks for the reply.
How can I transfer the site to the forum.francescomancuso.it subdomain?
Is there a special procedure or just change the settings of the app.yaml file and the nginx configuration?
Thanks for your help
You need to revert the changes you made for subfolder, and change the domain name on your install once the new subdomain is in DNS.
Hopefully you have a backup from before you attempted to downgrade - take another backup before you attempt the above.
Then you’ll need to reestablish SSO.
Hi, thanks again for your reply.
I will try to transfer the forum.