diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -478,7 +478,6 @@
     'DifferentialParseRenderTestCase' => 'applications/differential/__tests__/DifferentialParseRenderTestCase.php',
     'DifferentialPathField' => 'applications/differential/customfield/DifferentialPathField.php',
     'DifferentialProjectReviewersField' => 'applications/differential/customfield/DifferentialProjectReviewersField.php',
-    'DifferentialProjectsField' => 'applications/differential/customfield/DifferentialProjectsField.php',
     'DifferentialQueryConduitAPIMethod' => 'applications/differential/conduit/DifferentialQueryConduitAPIMethod.php',
     'DifferentialQueryDiffsConduitAPIMethod' => 'applications/differential/conduit/DifferentialQueryDiffsConduitAPIMethod.php',
     'DifferentialRawDiffRenderer' => 'applications/differential/render/DifferentialRawDiffRenderer.php',
@@ -5131,7 +5130,6 @@
     'DifferentialParseRenderTestCase' => 'PhabricatorTestCase',
     'DifferentialPathField' => 'DifferentialCustomField',
     'DifferentialProjectReviewersField' => 'DifferentialCustomField',
-    'DifferentialProjectsField' => 'DifferentialCoreCustomField',
     'DifferentialQueryConduitAPIMethod' => 'DifferentialConduitAPIMethod',
     'DifferentialQueryDiffsConduitAPIMethod' => 'DifferentialConduitAPIMethod',
     'DifferentialRawDiffRenderer' => 'Phobject',
diff --git a/src/applications/differential/config/PhabricatorDifferentialConfigOptions.php b/src/applications/differential/config/PhabricatorDifferentialConfigOptions.php
--- a/src/applications/differential/config/PhabricatorDifferentialConfigOptions.php
+++ b/src/applications/differential/config/PhabricatorDifferentialConfigOptions.php
@@ -33,7 +33,6 @@
       new DifferentialReviewedByField(),
       new DifferentialSubscribersField(),
       new DifferentialRepositoryField(),
-      new DifferentialProjectsField(),
       new DifferentialViewPolicyField(),
 
       new DifferentialManiphestTasksField(),
diff --git a/src/applications/differential/customfield/DifferentialProjectsField.php b/src/applications/differential/customfield/DifferentialProjectsField.php
deleted file mode 100644
--- a/src/applications/differential/customfield/DifferentialProjectsField.php
+++ /dev/null
@@ -1,110 +0,0 @@
-<?php
-
-final class DifferentialProjectsField
-  extends DifferentialCoreCustomField {
-
-  public function getFieldKey() {
-    return 'phabricator:projects';
-  }
-
-  public function getFieldName() {
-    return pht('Tags');
-  }
-
-  public function getFieldDescription() {
-    return pht('Tag projects.');
-  }
-
-  public function shouldAppearInPropertyView() {
-    return false;
-  }
-
-  public function shouldAppearInApplicationTransactions() {
-    return true;
-  }
-
-  protected function readValueFromRevision(
-    DifferentialRevision $revision) {
-    if (!$revision->getPHID()) {
-      return array();
-    }
-
-    $projects = PhabricatorEdgeQuery::loadDestinationPHIDs(
-      $revision->getPHID(),
-      PhabricatorProjectObjectHasProjectEdgeType::EDGECONST);
-    $projects = array_reverse($projects);
-
-    return $projects;
-  }
-
-  public function getNewValueForApplicationTransactions() {
-    return array('=' => array_fuse($this->getValue()));
-  }
-
-  public function readValueFromRequest(AphrontRequest $request) {
-    $this->setValue($request->getArr($this->getFieldKey()));
-  }
-
-  public function renderEditControl(array $handles) {
-    return id(new AphrontFormTokenizerControl())
-      ->setUser($this->getViewer())
-      ->setName($this->getFieldKey())
-      ->setDatasource(new PhabricatorProjectDatasource())
-      ->setValue($this->getValue())
-      ->setLabel($this->getFieldName());
-  }
-
-  public function getApplicationTransactionType() {
-    return PhabricatorTransactions::TYPE_EDGE;
-  }
-
-  public function shouldAppearInCommitMessage() {
-    return true;
-  }
-
-  public function shouldAllowEditInCommitMessage() {
-    return true;
-  }
-
-  public function shouldOverwriteWhenCommitMessageIsEdited() {
-    return true;
-  }
-
-  public function getCommitMessageLabels() {
-    return array(
-      'Tags',
-      'Project',
-      'Projects',
-    );
-  }
-
-  public function getRequiredHandlePHIDsForCommitMessage() {
-    return $this->getValue();
-  }
-
-  public function renderCommitMessageValue(array $handles) {
-    return $this->renderObjectList($handles);
-  }
-
-  public function shouldAppearInConduitDictionary() {
-    // To improve performance, we exclude this field from Conduit results.
-    // See T11404 for discussion. In modern "differential.revision.search",
-    // this information is available efficiently as an attachment.
-    return false;
-  }
-
-  public function getApplicationTransactionMetadata() {
-    return array(
-      'edge:type' => PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
-    );
-  }
-
-  public function parseValueFromCommitMessage($value) {
-    return $this->parseObjectList(
-      $value,
-      array(
-        PhabricatorProjectProjectPHIDType::TYPECONST,
-      ));
-  }
-
-}