+block
+~~~~~
+Block the given contacts or groups (no messages will be received). This change is only
+local but can be synchronized to other devices by using `sendContacts` (see
+below).
+
+[CONTACT [CONTACT ...]]::
+ Specify the phone numbers of contacts that should be blocked.
+
+*-g* [GROUP [GROUP ...]], *--group* [GROUP [GROUP ...]]::
+ Specify the group IDs that should be blocked in base64 encoding.
+
+unblock
+~~~~~~~
+Unblock the given contacts or groups (messages will be received again). This change is only
+local but can be synchronized to other devices by using `sendContacts` (see
+below).
+
+[CONTACT [CONTACT ...]]::
+Specify the phone numbers of contacts that should be unblocked.
+
+*-g* [GROUP [GROUP ...]], *--group* [GROUP [GROUP ...]]::
+Specify the group IDs that should be unblocked in base64 encoding.
+