Updating Gravity Forms kills this plugin and wp-admin.
Be sure to disable +Stripe before upgrading Gravity Forms.
(see also: http://wordpress.org/support/topic/new-gravity-forms-update-kills-this-plugin )
I just experienced the same as described in the link above - no php errors in my case, just a white screen when trying to access wp-admin - I'd argue that this is far worse than getting php errors. This occurred after upgrading Gforms to version 1.8
I rolled everything back to its state prior to the upgrade, disabled +Stripe
It would be great if the developers would include this info prominently somewhere; The readme and the +stripe settings page would be a great start.
It's not a huge deal to deactivate +stripe prior to upgrading gforms, but I'm kind of nervous about using this on a production site and turning it over to a client.