I just updated my Discourse at gradientdescent.co the same way I always do. (Edit: That is, via the one-click browser upgrade.) There was an error during the 2.4.0.beta8 update. It didn’t complete the first time I attempted the update. I tried it again and the update said it completed successfully, but now the site is bricked. I went into the console on Digital Ocean and rebooted my server. I logged in and restarted the Discourse docker for good measure. But I’m still getting the white page of death.
Edit: If you’re having this issue, the best course of action seems to be to use the console/terminal and type in these commands:
cd /var/discourse
git pull
./launcher rebuild app
If you haven’t already updated to 2.4.0.beta8, avoid using the one-click browser upgrade.