We released a code change to our Distribution Server Fleet at 9:00 am. However, one of our API servers had previously failed to upgrade correctly to PHP 7.3, so a trailing comma in the code release (which is only valid in 7.3) caused errors for all users hitting this server. We rolled back the code change to fix the issue quickly. We have now upgraded all the servers, and the updated code is running successfully. As our development and staging servers had all successfully upgraded to 7.3, this issue was not caught earlier.