Currently, the oldest version that can be installed via the Maxon App is R23 (23.110) both in Maxon One and Cinema 4D subscription licenses.
Please see below:
If you have purchased a Cinema 4D subscription license (also includes the Cinema 4D+Redshift bundle) can use versions from R21 to the latest.
However, Maxon One subscription license users cannot use older R21 and S22 versions.
Additionally, since both R21 and S22 are old versions, it is not possible to install and assign licenses through the Maxon App.
If you need the installer, please contact Support Team for further help.