Per the June 10, 2026 release note, the configuration option to not enroll your cluster in a release channel is...

Per the June 10, 2026 release note, the configuration option to not enroll your cluster in a release channel is deprecated, and will be removed on June 14, 2027. In alignment with this deprecation, creating new clusters not enrolled in a release channel is now only allowed for existing customers. New customers can use a release channel, where you can achieve the same functionality as not enrolling your cluster in a release channel. For more information, see Clusters not enrolled in a release channel.