diff --git a/src/applications/maniphest/conduit/ManiphestConduitAPIMethod.php b/src/applications/maniphest/conduit/ManiphestConduitAPIMethod.php
--- a/src/applications/maniphest/conduit/ManiphestConduitAPIMethod.php
+++ b/src/applications/maniphest/conduit/ManiphestConduitAPIMethod.php
@@ -192,20 +192,6 @@
       return;
     }
 
-    $event = new PhabricatorEvent(
-      PhabricatorEventType::TYPE_MANIPHEST_WILLEDITTASK,
-      array(
-        'task'          => $task,
-        'new'           => $is_new,
-        'transactions'  => $transactions,
-      ));
-    $event->setUser($request->getUser());
-    $event->setConduitRequest($request);
-    PhutilEventEngine::dispatchEvent($event);
-
-    $task = $event->getValue('task');
-    $transactions = $event->getValue('transactions');
-
     $content_source = PhabricatorContentSource::newForSource(
       PhabricatorContentSource::SOURCE_CONDUIT,
       array());
@@ -221,17 +207,6 @@
 
     $editor->applyTransactions($task, $transactions);
 
-    $event = new PhabricatorEvent(
-      PhabricatorEventType::TYPE_MANIPHEST_DIDEDITTASK,
-      array(
-        'task'          => $task,
-        'new'           => $is_new,
-        'transactions'  => $transactions,
-      ));
-    $event->setUser($request->getUser());
-    $event->setConduitRequest($request);
-    PhutilEventEngine::dispatchEvent($event);
-
     // reload the task now that we've done all the fun stuff
     return id(new ManiphestTaskQuery())
       ->setViewer($request->getUser())
diff --git a/src/docs/user/userguide/events.diviner b/src/docs/user/userguide/events.diviner
--- a/src/docs/user/userguide/events.diviner
+++ b/src/docs/user/userguide/events.diviner
@@ -5,6 +5,10 @@
 
 = Overview =
 
+(WARNING) The event system is an artifact of a bygone era. Use of the event
+system is strongly discouraged. We have been removing events since 2013 and
+will continue to remove events in the future.
+
 Phabricator and Arcanist allow you to install custom runtime event listeners
 which can react to certain things happening (like a Maniphest Task being edited
 or a user creating a new Differential Revision) and run custom code to perform
@@ -130,42 +134,6 @@
   - `specification` Parameters that will be used to invoke the
     `differential.createrevision` Conduit call.
 
-== Maniphest: Will Edit Task ==
-
-The constant for this event is
-`PhabricatorEventType::TYPE_MANIPHEST_WILLEDITTASK`.
-
-This event is dispatched before a task is edited, and allows you to respond to
-or alter the edit. Data available on this event:
-
-  - `task` The @{class:ManiphestTask} being edited.
-  - `transactions` The list of edits (objects of class
-    @{class:ManiphestTransaction}) being applied.
-  - `new` A boolean indicating if this task is being created.
-  - `mail` If this edit originates from email, the
-    @{class:PhabricatorMetaMTAReceivedMail} object.
-
-This is similar to the next event (did edit task) but occurs before the edit
-begins.
-
-== Maniphest: Did Edit Task ==
-
-The constant for this event is
-`PhabricatorEventType::TYPE_MANIPHEST_DIDEDITTASK`.
-
-This event is dispatched after a task is edited, and allows you to react to the
-edit. Data available on this event:
-
-  - `task` The @{class:ManiphestTask} that was edited.
-  - `transactions` The list of edits (objects of class
-    @{class:ManiphestTransaction}) that were applied.
-  - `new` A boolean indicating if this task was newly created.
-  - `mail` If this edit originates from email, the
-    @{class:PhabricatorMetaMTAReceivedMail} object.
-
-This is similar to the previous event (will edit task) but occurs after the
-edit completes.
-
 == Differential: Will Mark Generated ==
 
 The constant for this event is
diff --git a/src/infrastructure/events/constant/PhabricatorEventType.php b/src/infrastructure/events/constant/PhabricatorEventType.php
--- a/src/infrastructure/events/constant/PhabricatorEventType.php
+++ b/src/infrastructure/events/constant/PhabricatorEventType.php
@@ -6,9 +6,6 @@
  */
 final class PhabricatorEventType extends PhutilEventType {
 
-  const TYPE_MANIPHEST_WILLEDITTASK         = 'maniphest.willEditTask';
-  const TYPE_MANIPHEST_DIDEDITTASK          = 'maniphest.didEditTask';
-
   const TYPE_DIFFERENTIAL_WILLMARKGENERATED = 'differential.willMarkGenerated';
 
   const TYPE_DIFFUSION_DIDDISCOVERCOMMIT    = 'diffusion.didDiscoverCommit';