Can I schedule a booster to start or stop on a specific date? (Essential Free Shipping Upsell app)
No. Boosters don't have start or end dates. A booster is either published or unpublished. Publish a booster to make it live, and unpublish it to stop it showing.
If you want a booster to run only during a sale, publish it when the sale starts and unpublish it when the sale ends.