We’ve redeployed the web server hosts powering www.ibiblio.org. These now have newer operating systems and more php functions disabled. If your site was working this morning before 11:28am Eastern and now is not, please note your collection’s full URL in a reply here and we will investigate.
EDIT to add: the default PHP version also changed from 7.1.x to 7.3.x during this redeploy.