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
@@ -572,7 +572,6 @@
     'DifferentialTestPlanCommitMessageField' => 'applications/differential/field/DifferentialTestPlanCommitMessageField.php',
     'DifferentialTestPlanField' => 'applications/differential/customfield/DifferentialTestPlanField.php',
     'DifferentialTitleCommitMessageField' => 'applications/differential/field/DifferentialTitleCommitMessageField.php',
-    'DifferentialTitleField' => 'applications/differential/customfield/DifferentialTitleField.php',
     'DifferentialTransaction' => 'applications/differential/storage/DifferentialTransaction.php',
     'DifferentialTransactionComment' => 'applications/differential/storage/DifferentialTransactionComment.php',
     'DifferentialTransactionEditor' => 'applications/differential/editor/DifferentialTransactionEditor.php',
@@ -5236,7 +5235,6 @@
     'DifferentialTestPlanCommitMessageField' => 'DifferentialCommitMessageField',
     'DifferentialTestPlanField' => 'DifferentialCoreCustomField',
     'DifferentialTitleCommitMessageField' => 'DifferentialCommitMessageField',
-    'DifferentialTitleField' => 'DifferentialCoreCustomField',
     'DifferentialTransaction' => 'PhabricatorModularTransaction',
     'DifferentialTransactionComment' => 'PhabricatorApplicationTransactionComment',
     'DifferentialTransactionEditor' => 'PhabricatorApplicationTransactionEditor',
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
@@ -25,7 +25,6 @@
     $custom_field_type = 'custom:PhabricatorCustomFieldConfigOptionType';
 
     $fields = array(
-      new DifferentialTitleField(),
       new DifferentialSummaryField(),
       new DifferentialTestPlanField(),
       new DifferentialReviewersField(),
diff --git a/src/applications/differential/customfield/DifferentialTitleField.php b/src/applications/differential/customfield/DifferentialTitleField.php
deleted file mode 100644
--- a/src/applications/differential/customfield/DifferentialTitleField.php
+++ /dev/null
@@ -1,125 +0,0 @@
-<?php
-
-final class DifferentialTitleField
-  extends DifferentialCoreCustomField {
-
-  public function getFieldKey() {
-    return 'differential:title';
-  }
-
-  public function getFieldKeyForConduit() {
-    return 'title';
-  }
-
-  public function getFieldName() {
-    return pht('Title');
-  }
-
-  public function getFieldDescription() {
-    return pht('Stores the revision title.');
-  }
-
-  public static function getDefaultTitle() {
-    return pht('<<Replace this line with your Revision Title>>');
-  }
-
-  protected function readValueFromRevision(
-    DifferentialRevision $revision) {
-    return $revision->getTitle();
-  }
-
-  protected function writeValueToRevision(
-    DifferentialRevision $revision,
-    $value) {
-    $revision->setTitle($value);
-  }
-
-  protected function getCoreFieldRequiredErrorString() {
-    return pht('You must choose a title for this revision.');
-  }
-
-  public function readValueFromRequest(AphrontRequest $request) {
-    $this->setValue($request->getStr($this->getFieldKey()));
-  }
-
-  protected function isCoreFieldRequired() {
-    return true;
-  }
-
-  public function renderEditControl(array $handles) {
-    return id(new AphrontFormTextAreaControl())
-      ->setHeight(AphrontFormTextAreaControl::HEIGHT_VERY_SHORT)
-      ->setName($this->getFieldKey())
-      ->setValue($this->getValue())
-      ->setError($this->getFieldError())
-      ->setLabel($this->getFieldName());
-  }
-
-  public function getApplicationTransactionTitle(
-    PhabricatorApplicationTransaction $xaction) {
-    $author_phid = $xaction->getAuthorPHID();
-    $old = $xaction->getOldValue();
-    $new = $xaction->getNewValue();
-
-    if (strlen($old)) {
-      return pht(
-        '%s retitled this revision from "%s" to "%s".',
-        $xaction->renderHandleLink($author_phid),
-        $old,
-        $new);
-    } else {
-      return pht(
-        '%s created this revision.',
-        $xaction->renderHandleLink($author_phid));
-    }
-  }
-
-  public function getApplicationTransactionTitleForFeed(
-    PhabricatorApplicationTransaction $xaction) {
-
-    $object_phid = $xaction->getObjectPHID();
-    $author_phid = $xaction->getAuthorPHID();
-    $old = $xaction->getOldValue();
-    $new = $xaction->getNewValue();
-
-    if (strlen($old)) {
-      return pht(
-        '%s retitled %s, from "%s" to "%s".',
-        $xaction->renderHandleLink($author_phid),
-        $xaction->renderHandleLink($object_phid),
-        $old,
-        $new);
-    } else {
-      return pht(
-        '%s created %s.',
-        $xaction->renderHandleLink($author_phid),
-        $xaction->renderHandleLink($object_phid));
-    }
-  }
-
-  public function shouldAppearInCommitMessage() {
-    return true;
-  }
-
-  public function shouldOverwriteWhenCommitMessageIsEdited() {
-    return true;
-  }
-
-  public function validateCommitMessageValue($value) {
-    if (!strlen($value)) {
-      throw new DifferentialFieldValidationException(
-        pht(
-          'You must provide a revision title in the first line '.
-          'of your commit message.'));
-    }
-
-    if (preg_match('/^<<.*>>$/', $value)) {
-      throw new DifferentialFieldValidationException(
-        pht(
-          'Replace the line "%s" with a human-readable revision title which '.
-          'describes the changes you are making.',
-          self::getDefaultTitle()));
-    }
-  }
-
-}
diff --git a/src/applications/differential/storage/DifferentialTransaction.php b/src/applications/differential/storage/DifferentialTransaction.php
--- a/src/applications/differential/storage/DifferentialTransaction.php
+++ b/src/applications/differential/storage/DifferentialTransaction.php
@@ -22,6 +22,23 @@
     return 'DifferentialRevisionTransactionType';
   }
 
+  protected function newFallbackModularTransactionType() {
+    // TODO: This allows us to render modern strings for older transactions
+    // without doing a migration. At some point, we should do a migration and
+    // throw this away.
+
+    $xaction_type = $this->getTransactionType();
+    if ($xaction_type == PhabricatorTransactions::TYPE_CUSTOMFIELD) {
+      switch ($this->getMetadataValue('customfield:key')) {
+        case 'differential:title':
+          return new DifferentialRevisionTitleTransaction();
+      }
+    }
+
+    return parent::newFallbackModularTransactionType();
+  }
+
+
   public function setIsCommandeerSideEffect($is_side_effect) {
     $this->isCommandeerSideEffect = $is_side_effect;
     return $this;
diff --git a/src/applications/transactions/storage/PhabricatorModularTransaction.php b/src/applications/transactions/storage/PhabricatorModularTransaction.php
--- a/src/applications/transactions/storage/PhabricatorModularTransaction.php
+++ b/src/applications/transactions/storage/PhabricatorModularTransaction.php
@@ -46,7 +46,7 @@
     $key = $this->getTransactionType();
 
     if (empty($types[$key])) {
-      $type = new PhabricatorCoreVoidTransaction();
+      $type = $this->newFallbackModularTransactionType();
     } else {
       $type = clone $types[$key];
     }
@@ -56,6 +56,10 @@
     return $type;
   }
 
+  protected function newFallbackModularTransactionType() {
+    return new PhabricatorCoreVoidTransaction();
+  }
+
   final public function generateOldValue($object) {
     return $this->getTransactionImplementation()->generateOldValue($object);
   }