You can now opt in or out of generating and delivering event log files. Previously, all instances received event log files automatically. With this update, event log files are only generated and delivered to instances that opt in to receive event log files. This update automatically disables event log file generation for Developer and Trial editions, and for instances that don’t have the Event Monitoring add-on subscription by default. If you have Salesforce Shield or Salesforce Event Monitoring add-on subscriptions, you’re opted in to receiving event log files by default. This update is available starting in Spring ’23.
Where: This change applies to Lightning Experience and Salesforce Classic in Enterprise, Performance, Unlimited, and Developer Editions.
When: Salesforce enforces this update in Summer ’23. Salesforce provides this preference setting now so that you can choose whether to turn on or off event log file generation in advance. If you want to continue to receive event log files, ensure that this preference setting is turned on. To get the major release upgrade date for your instance, go to Trust Status, search for your instance, and click the maintenance tab.
How: To continue to receive event log files when this update takes effect, from Setup, in the Quick Find box, enter Event Monitoring, and then select Event Monitoring Settings. Then turn on Generate event log files, and save your changes.
Opt in for Event Log File Generation (Release Update) (salesforce.com)