Updates to reflect the use of JupyterHub 3

Author: consideRatio

docs/source/administrator/upgrading/upgrade-1-to-2.md

@@ -49,11 +49,11 @@ and the configuration reference entries under
 
 ## JupyterHub 2 and related hub components
 
-Z2JH 2.0.0 upgrades JupyterHub to the 2.\* series, and also upgrades all hub components.
+Z2JH 2.0.0 upgrades from JupyterHub 1 directly to JupyterHub 3, and also upgrades all hub components.
 If you are using any custom JupyterHub services, addons, API integrations, or extra configuration, you should review the breaking changes in the
-[JupyterHub 2.x changelog](https://jupyterhub.readthedocs.io/en/2.3.1/changelog.html).
+major releases of JupyterHub 2 and 3 in the [JupyterHub changelog](https://jupyterhub.readthedocs.io/en/latest/changelog.html).
 
-JupyterHub 2 updates the database schema, which means a migration takes place when you upgrade JupyterHub.
+JupyterHub 2 and 3 updates the database schema, which means a migration takes place when you upgrade JupyterHub.
 Z2JH automatically handles the upgrade if you are using sqlite (`hub.db.type = 'sqlite-pvc'`, the default), but it may not be possible to downgrade to older releases after this.
 When using sqlite, JupyterHub automatically creates a backup in the `hub-db` volume,
 which can be restored manually if you need to downgrade.

docs/source/changelog.md

@@ -23,9 +23,9 @@ Ensure you backup your system and test any upgrades if you plan to use this in p
 
 #### Highlights
 
-Z2JH 2.0.0 is the first major release since 1.0.0 was released in June 2021, and contains major upgrades to all JupyterHub components.
+Z2JH 2.0.0 is the first major release since 1.0.0 was released in June 2021, and contains major upgrades to all JupyterHub components, including a jump directly from JupyterHub 1 to JupyterHub 3.
 
-JupyterHub 3.x includes new RBAC support allowing fine-grained access control to hub services and servers.
+JupyterHub 2 and 3 includes new RBAC support allowing fine-grained access control to hub services and servers.
 
 JupyterLab, the next-generation Notebook interface, is now the default interface seen by users. This brings a full development environment with a large number of extensions developed by the Jupyter community.