Refresh Sandbox to the Preview Release After the Deadline

After the preview release deadline has passed, it is NOT possible to refresh a sandbox in Production and have it receive the new release upgrade. Due to strict technical limitations, no exceptions can be made to this rule.


Preview process:

1. Salesforce identifies the Sandbox instances that will receive the release preview and sets a date by which sandboxes need to exist on those instances to receive the preview.
2. On the preview release date, those previously identified instances are upgraded to the new release, and so all sandboxes that exist on those instances also receive the preview.
3. Going forward, all newly created or refreshed sandboxes will receive the same release version as the Production organization.

Notes: 

• The time that each instance is scheduled to be updated is published at trust.salesforce.com.
• Read the Sandbox Preview Instructions article.

Check Salesforce Sandbox Preview Guide to identify if the current instance of the sandbox will be in preview or non-preview for the upcoming release.

When you Can refresh a sandbox to a new release

• During the preview release period.
• Once your production organization has been upgraded.

When you Can NOT refresh a sandbox to a new release

• After the preview release deadline has passed.
• After the preview period, if your production organization has not yet been upgraded.

Notes:

• The sandbox preview works by temporarily configuring sandboxes to process on preview instances.
• After the preview deadline has passed, a production organization still on a previous release can not create or refresh a sandbox and have it land on a preview instance.
  However, clones of preview sandboxes will still be in preview.
  Review Unable to add or remove Sandbox to release preview without refresh.