Select the API Version for Lightning Locker
Where: This change applies to Lightning Experience, Lightning Communities, and all versions of the mobile app in all editions.
Why: We recommend updating your custom components to comply with the latest version, but we know that it can take some time. Your org could also depend on managed packages that third-party developers must update. Set Lightning Locker to use an older API version to give developers time to update their custom Lightning components and comply with Locker’s latest security enhancements.
How: From Setup, enter Session in the Quick Find box, and then select Session Settings. Select the API version for Use security enhancements in API version. Click Save.