Pre-Upgrade Maintenance Tasks in AEM

Before beginning your upgrade, it is important to follow these maintenance tasks to ensure that the system is ready

Ensure Sufficient Disk Space
Fully Back Up AEM
Back-Up Changes to /etc
Generate The quickstart.properties File
Configure Workflow and Audit Log Purging
Install, Configure, and Run The Pre-Upgrade Tasks
Disable Custom Login Modules
Remove Updates From The /install Directory
Stop Any Cold Standby Instances
Disable Custom Scheduled Jobs
Execute Offline Revision Cleanup
Execute Datastore Garbage Collection
Rotate Log Files