WordPress update 3.8.1 breaks customizr theme

We just updated to WordPress 3.8.1, and also updated all of our plugins. After these updates the customizr theme no longer works on the site, and the site shows a 504 error. Using any other theme the site works.

I tried de-activating all plugins, didn’t fix. Then deleted the customizr theme, re-installed, didn’t fix. Then deleted the customizr theme, re-installed the previous version before the latest update, didn’t fix.

Is there something that we can change in the customizr theme to get to this to work? In the meantime we will be using a different theme until this gets resolved. Thanks.