Salesforce Fact #852 | Preview and Non-preview sandbox
There are two types of sandboxes in terms of Salesforce release: Preview sandbox and Non-Preview sandbox. A preview sandbox provides early access to new features before the production upgrade. These sandboxes are upgraded automatically approximately 6 weeks before the production release. A non-preview sandbox is not upgraded early and is ideally upgraded after the production release. To check the release type of the sandbox, go to production org -> setup -> search for Sandboxes in quick search -> check the release type of the sandboxes. Reference: https://help.salesforce.com/s/articleView?id=sf.data_sandbox_preview.htm&type=5