The most recent beta release requires that you do a rebuild from the command line.
While self-hosted sites can usually keep up to date at the /admin/upgrade, a few times a year, you will see something like this:
I am offering a new service that will do these command line updates for you automatically, usually a few days after a new Beta is released (just to make sure that there are no problems).
For $300/year I will see that the components that make Discourse work are up to date.
See Automatic Rebuilds when They Are Needed – Literate Computing, LLC to sign up.
NOTE: This service is just for upgrades when a command line update is required. If you would like full support with off-site backups, monitoring, and continual upgrades, please see my maintenance packages.