diff --git a/resources/sql/autopatches/20160208.task.1.sql b/resources/sql/autopatches/20160208.task.1.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20160208.task.1.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_maniphest.maniphest_task
+  DROP projectPHIDs;
diff --git a/resources/sql/autopatches/20160208.task.2.sql b/resources/sql/autopatches/20160208.task.2.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20160208.task.2.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_maniphest.maniphest_task
+  DROP attached;
diff --git a/resources/sql/patches/migrate-maniphest-dependencies.php b/resources/sql/patches/migrate-maniphest-dependencies.php
--- a/resources/sql/patches/migrate-maniphest-dependencies.php
+++ b/resources/sql/patches/migrate-maniphest-dependencies.php
@@ -1,29 +1,3 @@
 <?php
 
-echo pht('Migrating task dependencies to edges...')."\n";
-$table = new ManiphestTask();
-$table->openTransaction();
-
-foreach (new LiskMigrationIterator($table) as $task) {
-  $id = $task->getID();
-  echo pht('Task %d: ', $id);
-
-  $deps = $task->getAttachedPHIDs(ManiphestTaskPHIDType::TYPECONST);
-  if (!$deps) {
-    echo "-\n";
-    continue;
-  }
-
-  $editor = new PhabricatorEdgeEditor();
-  foreach ($deps as $dep) {
-    $editor->addEdge(
-      $task->getPHID(),
-      ManiphestTaskDependsOnTaskEdgeType::EDGECONST,
-      $dep);
-  }
-  $editor->save();
-  echo pht('OKAY')."\n";
-}
-
-$table->saveTransaction();
-echo pht('Done.')."\n";
+// From 2013-2016, this migration moved dependent tasks to edges.
diff --git a/resources/sql/patches/migrate-maniphest-revisions.php b/resources/sql/patches/migrate-maniphest-revisions.php
--- a/resources/sql/patches/migrate-maniphest-revisions.php
+++ b/resources/sql/patches/migrate-maniphest-revisions.php
@@ -1,28 +1,3 @@
 <?php
 
-echo pht('Migrating task revisions to edges...')."\n";
-$table = new ManiphestTask();
-$table->establishConnection('w');
-
-foreach (new LiskMigrationIterator($table) as $task) {
-  $id = $task->getID();
-  echo pht('Task %d: ', $id);
-
-  $revs = $task->getAttachedPHIDs(DifferentialRevisionPHIDType::TYPECONST);
-  if (!$revs) {
-    echo "-\n";
-    continue;
-  }
-
-  $editor = new PhabricatorEdgeEditor();
-  foreach ($revs as $rev) {
-    $editor->addEdge(
-      $task->getPHID(),
-      ManiphestTaskHasRevisionEdgeType::EDGECONST,
-      $rev);
-  }
-  $editor->save();
-  echo pht('OKAY')."\n";
-}
-
-echo pht('Done.')."\n";
+// From 2013-2016, this migration moved revisions attached to tasks to edges.
diff --git a/src/applications/maniphest/storage/ManiphestTask.php b/src/applications/maniphest/storage/ManiphestTask.php
--- a/src/applications/maniphest/storage/ManiphestTask.php
+++ b/src/applications/maniphest/storage/ManiphestTask.php
@@ -34,8 +34,6 @@
   protected $viewPolicy = PhabricatorPolicies::POLICY_USER;
   protected $editPolicy = PhabricatorPolicies::POLICY_USER;
 
-  protected $projectPHIDs = array();
-
   protected $ownerOrdering;
   protected $spacePHID;
   protected $properties = array();
@@ -45,9 +43,6 @@
   private $customFields = self::ATTACHABLE;
   private $edgeProjectPHIDs = self::ATTACHABLE;
 
-  // TODO: This field is unused and should eventually be removed.
-  protected $attached = array();
-
   public static function initializeNewTask(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
@@ -72,9 +67,6 @@
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_SERIALIZATION => array(
-        'ccPHIDs' => self::SERIALIZATION_JSON,
-        'attached' => self::SERIALIZATION_JSON,
-        'projectPHIDs' => self::SERIALIZATION_JSON,
         'properties' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
@@ -88,11 +80,6 @@
         'ownerOrdering' => 'text64?',
         'originalEmailSource' => 'text255?',
         'subpriority' => 'double',
-
-        // T6203/NULLABILITY
-        // This should not be nullable. It's going away soon anyway.
-        'ccPHIDs' => 'text?',
-
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_phid' => null,
@@ -143,10 +130,6 @@
       ManiphestTaskDependedOnByTaskEdgeType::EDGECONST);
   }
 
-  public function getAttachedPHIDs($type) {
-    return array_keys(idx($this->attached, $type, array()));
-  }
-
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(ManiphestTaskPHIDType::TYPECONST);
   }