diff --git a/admin_manual/configuration_files/file_sharing_configuration.rst b/admin_manual/configuration_files/file_sharing_configuration.rst
index 238f7352f..880b55b1c 100644
--- a/admin_manual/configuration_files/file_sharing_configuration.rst
+++ b/admin_manual/configuration_files/file_sharing_configuration.rst
@@ -1,3 +1,5 @@
+.. _file-sharing-configuration:
+
 ============
 File Sharing
 ============
diff --git a/admin_manual/configuration_server/occ_command.rst b/admin_manual/configuration_server/occ_command.rst
index 6f2349811..01409b047 100644
--- a/admin_manual/configuration_server/occ_command.rst
+++ b/admin_manual/configuration_server/occ_command.rst
@@ -515,8 +515,14 @@ bernie::
 
  sudo -u www-data php occ dav:sync-birthday-calendar bernie
 
-``dav:sync-system-addressbook`` synchronizes all users to the system
-addressbook::
+
+.. _occ-dav-sync-system-address-book:
+
+Sync system address book
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+``dav:sync-system-addressbook`` synchronizes all users to the :ref:`system
+address book<system-address-book>`::
 
  sudo -u www-data php occ dav:sync-system-addressbook
 
diff --git a/admin_manual/configuration_user/profile_configuration.rst b/admin_manual/configuration_user/profile_configuration.rst
index 05db50f15..dda5c4352 100644
--- a/admin_manual/configuration_user/profile_configuration.rst
+++ b/admin_manual/configuration_user/profile_configuration.rst
@@ -1,3 +1,5 @@
+.. _profile:
+
 =====================
 Profile configuration
 =====================
@@ -9,6 +11,8 @@ Personal info settings under the Personal settings section.
 As an administrator you may change the default for new users and may also
 disable profile globally to remove all profile functionality.
 
+Profile properties are also written into the :ref:`system address book<system-address-book>`.
+
 To enable or disable profile by default for new users switch the toggle in
 Basic settings under the Administration settings section.
 
@@ -35,6 +39,8 @@ To disable profile globally add the following line to your ``config.php``
 Please refer to :doc:`../configuration_server/config_sample_php_parameters` for
 all available ``config.php`` options.
 
+.. _profile-property-scopes:
+
 Property scopes
 ---------------
 
diff --git a/admin_manual/groupware/contacts.rst b/admin_manual/groupware/contacts.rst
new file mode 100644
index 000000000..d98cd1fb5
--- /dev/null
+++ b/admin_manual/groupware/contacts.rst
@@ -0,0 +1,38 @@
+==================
+Contacts / CardDAV
+==================
+
+Nextcloud ships a CardDAV backend for users to store and share their address books and contacts.
+
+.. _system-address-book:
+
+System Address Book
+-------------------
+
+.. versionchanged:: 27
+    The system address book is now accessible to all Nextcloud users
+
+Nextcloud maintains a read-only address book containing contact information of all users of the instance.
+
+Disabled users are removed from this address book.
+
+Privacy and User Property Scopes
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Contact information in the system address book is taken from users' :ref:`profile information<profile>`. Profile properties are only written to the system contact if the :ref:`scope<profile-property-scopes>` is set to *Local* or higher.
+
+Users who set all their property scopes to *Private* are removed from the system address book and therefore not seen by other users.
+
+:ref:`File sharing settings<file-sharing-configuration>` controls the enumeration of other users.
+
+* If username autocompletion is not allowed, the system address book will only show user's own system contact but no other contacts.
+* If username autocompletion is allowed, users will see contact cards for all other users.
+
+  * If autocompletion is limited to users within the same groups, users will see contact cards for other users in shared groups.
+  * If autocompletion is limited to matching phone numbers, the system address book will only show user's own system contact but no other contacts.
+  * If autocompletion is limited to users within the same groups **and** matching phone numbers, users will see contact cards for other users in shared groups.
+
+Address Book Sync
+^^^^^^^^^^^^^^^^^
+
+The address book is updated automatically with every added, modified, disabled or removed user. Admins can also trigger a full rewrite of the address book :ref:`with occ<occ-dav-sync-system-address-book>`.
diff --git a/admin_manual/groupware/index.rst b/admin_manual/groupware/index.rst
index 753447f16..4ab89d8c0 100644
--- a/admin_manual/groupware/index.rst
+++ b/admin_manual/groupware/index.rst
@@ -7,4 +7,5 @@ Groupware
     :maxdepth: 2
 
     calendar
+    contacts
     mail
\ No newline at end of file