Before you upgrade your application, ensure that you complete all of the following tasks.

1. Ensure that you can stop and start the application server.
2. Before starting an update, and before backing up your system, review the database policies and application permissions that are used by your Pega Platform update. Determine whether the application is permitted to update the database automatically or if you must generate the database scripts that your organization will use to manually make schema changes.
3. Update to the latest version of Pega Platform 8.5, and ensure that you can log in as an administrator. For more information, see the Pega Platform Update Guide for your environment on the Deploy Pega Platform page.
4. If you have used any of the Pega Foundation for Communications rules in your application, upgrade to and verify Pega Foundation for Communications 8.5.
   Note: Starting from version 8.5, there is no dependency between Pega Customer Decision Hub for Communications and Pega Foundation for Communications.
   For more information, see Optional: Adding Pega Foundation for Communications to your application.
5. Upgrade to and verify Pega Customer Decision Hub 8.5. For information, see the Upgrade Guide on the Pega Customer Decision Hub product page.

   Apply the required hotfixes by using the Hotfix Manager. For more information, see Hotfix management.

   For the list of hotfixes for Pega Customer Decision Hub, see the Pega Customer Decision Hub hotfixes page.

6. Back up the existing database and all application data on the app-server level.
7. Log on to your application as an administrator.
8. In Dev Studio, click ConfigureDecisioningDecisionsData FlowsBatch Processing and then make sure that no data flow runs are in progress.
9. If you are not running a cloud upgrade, disable agent schedules by performing the following actions:
   1. In Dev Studio, click RecordsSysAdminAgent Schedule.
   2. Open all Pega Customer Decision Hub agent schedules. That includes the following schedules:
      • PegaMKT-Engine
      • PegaMKT-PushNotification
      • PegaMKT-Install
      • PegaMKT-FieldMarketing (if you installed it)
   3. Clear the Enable this agent check box for every agent that you disable.
   4. Click Save.
   Note: If you do not disable agent schedules, the agents automatically restart after the upgrade and the existing scheduled queue items fail to run. This results in a list of failed queue items that you must address manually.