The configuration option to not enroll your cluster in a release channel (known as No channel, formerly as Static) is...

The configuration option to not enroll your cluster in a release channel (known as No channel, formerly as Static) is now deprecated, and will be removed on June 14, 2027. For any clusters not enrolled in a release channel, we recommend that you enroll the cluster before this date. After the removal date, GKE will enroll all remaining clusters in the Stable channel. For more information about this deprecation and how you can achieve the same functionality with release channels, see Clusters not enrolled in a release channel.