Target a Specific Release for Your Unlocked Packages During Salesforce Release Transitions

During major Salesforce release transitions, you can specify preview or previous when creating a package version. Specifying the release version for a package allows you to test upcoming features, run regression tests, and support customers regardless of which Salesforce release their org is on. Previously, you could only create package versions that matched the Salesforce release your Dev Hub org was on.

To create a package version based on a preview or previous Salesforce release version, create a scratch org definition file that includes either:

1{
2    "release": "previous"
3}

1{
2    "release": "preview"
3}

In the sfdx-project.json file, set the sourceApiVersion to correspond with the release version of the package version you’re creating. If you are targeting a previous release, any sourceApiVersion value below the current release is accepted.

Then when you create your package version, specify the scratch org definition file.

1sf package version create --package pkgA --definition-file config/project-scratch-def.json

Preview start date is when sandbox instances are upgraded. Preview end date is when all instances are on the GA release.

Release Version	Preview Start Date	Preview End Date
Spring ’26	January 11, 2026	February 21, 2026
Summer ’26	May 10, 2026	June 13, 2026
Winter ’27	August 30, 2026	October 10, 2026