The release notes are available here:
http://docs.apigee.com/release-notes/content/apigee-release-notes
For Apigee Cloud customers -
Cloud customers hosted on Pantheon should apply updates to their site using the Pantheon dashboard:
http://apigee.com/docs/developer-services/content/working-pantheon#maintainyoursite-applyanapigeeupdatetothedeveloperservicesportal
and make sure all environments have been patched using the standard workflow:
http://helpdesk.getpantheon.com/customer/portal/articles/383609-using-the-pantheon-workflow
For Apigee Private Cloud customers -
Apigee Private Cloud customers should make sure their systems are following Drupal security advisories:
https://www.drupal.org/security
Follow the following process to update Drupal core and contributed modules:
https://docs.apigee.com/private-cloud/v4.50.00/portal-upgrading-drupal
---
This notification has been sent to anyone subscribed to "Drupal-based (alternative)", if you you do not want to receive notifications about Developer Portal please click the "manage your subscription" link in the notification email footer to modify your subscription choices.