Drupal commerce update to 1.14 from 1.13 - breaks checkout screen
There is no way for anyone to diagnose the issue with the information given. A blank page typically means a PHP error has interrupted the page request. When you encounter situations like this, look to your PHP / Apache error logs to see what clues is gives you.

I'm not aware of anything in the Commerce 1.14 release that should cause the checkout form to suddenly break, but perhaps it's related to some other contributed module on your site. If you track it down to a core problem that you can reproduce on a clean install of Commerce Kickstart 1.x, feel free to open a bug report in the Drupal Commerce issue queue.