We’re wrapping up the development period and entering the stabilization phase of the Humble release. This means that ros_base packages are now feature and API frozen in Rolling Ridley until we branch Humble from Rolling on 2022-04-18. At that time, feature and API changes can be merged into the Rolling branches once again.
You can find more info on the Humble release timeline here: ROS 2 Humble Hawksbill (codename ‘humble’; May, 2022) — ROS 2 Documentation: Rolling documentation.