+h2(#main). development main (as of 2022-03-08)
+
+"previous: Upgrading to 2.3.0":#v2_3_0
+
+h3. Ubuntu 18.04 Arvados Python packages now depend on python-3.8
+
+Ubuntu 18.04 ships with Python 3.6 as the default version of Python 3. Ubuntu also ships a version of Python 3.8, and the Arvados Python packages (@python3-arvados-cwl-runner@, @python3-arvados-fuse@, @python3-arvados-python-client@, @python3-arvados-user-activity@ and @python3-crunchstat-summary@) now depend on the @python-3.8@ system package.
+
+This means that they are now installed under @/usr/share/python3.8@ (before, the path was @/usr/share/python3@). If you rely on the @python3@ executable from the packages (e.g. to load a virtualenv), you may need to update the path to that executable.
+
+h3. Minimum supported Ruby version is now 2.6
+
+The minimum supported Ruby version is now 2.6. If you are running Arvados on Debian 10 or Ubuntu 18.04, you may need to switch to using RVM or upgrade your OS. See "Install Ruby and Bundler":../install/ruby.html for more information.
+
+h3. Anonymous token changes
+
+The anonymous token configured in @Users.AnonymousUserToken@ must now be 32 characters or longer. This was already the suggestion in the documentation, now it is enforced. The @script/get_anonymous_user_token.rb@ script that was needed to register the anonymous user token in the database has been removed. Registration of the anonymous token is no longer necessary. If the anonymous token in @config.yml@ is specified as a full V2 token, that will now generate a warning - it should be updated to list just the secret (i.e. the part after the last forward slash).
+
+h3. Preemptible instance types are used automatically, if any are configured
+
+The default behavior for selecting "preemptible instances":{{site.baseurl}}/admin/spot-instances.html has changed. If your configuration lists any instance types with @Preemptible: true@, all child (non-top-level) containers will automatically be scheduled on preemptible instances. To avoid using preemptible instances except when explicitly requested by clients, add @AlwaysUsePreemptibleInstances: false@ in the @Containers@ config section. (Previously, preemptible instance types were never used unless the configuration specified @UsePreemptibleInstances: true@. That flag has been removed.)
+
+h3. Role groups are visible to all users by default
+
+The permission model has changed such that all role groups are visible to all active users. This enables users to share objects with groups they don't belong to. To preserve the previous behavior, where role groups are only visible to members and admins, add @RoleGroupsVisibleToAll: false@ to the @Users@ section of your configuration file.
+
+h3. Default LSF arguments have changed
+
+If you use LSF and your configuration specifies @Containers.LSF.BsubArgumentsList@, you should update it to include the new arguments (@"-R", "select[mem>=%MMB]", ...@, see "configuration reference":{{site.baseurl}}/admin/config.html). Otherwise, containers that are too big to run on any LSF host will remain in the LSF queue instead of being cancelled.
+
+h3. Previously trashed role groups will be deleted
+
+Due to a bug in previous versions, the @DELETE@ operation on a role group caused the group to be flagged as trash in the database, but continue to grant permissions regardless. After upgrading, any role groups that had been trashed this way will be deleted. This might surprise some users if they were relying on permissions that were still in effect due to this bug. Future @DELETE@ operations on a role group will immediately delete the group and revoke the associated permissions.
+
+h3. Users are visible to other users by default