diff --git a/resources/sql/patches/20130611.migrateoauth.php b/resources/sql/patches/20130611.migrateoauth.php
--- a/resources/sql/patches/20130611.migrateoauth.php
+++ b/resources/sql/patches/20130611.migrateoauth.php
@@ -1,66 +1,14 @@
 <?php
 
-// NOTE: We aren't using PhabricatorUserOAuthInfo anywhere here because it is
-// getting nuked in a future diff.
-
 $table = new PhabricatorUser();
+$conn = $table->establishConnection('w');
 $table_name = 'user_oauthinfo';
-$conn_w = $table->establishConnection('w');
-
-$xaccount = new PhabricatorExternalAccount();
-
-echo pht('Migrating OAuth to %s...', 'ExternalAccount')."\n";
 
-$domain_map = array(
-  'disqus'      => 'disqus.com',
-  'facebook'    => 'facebook.com',
-  'github'      => 'github.com',
-  'google'      => 'google.com',
-);
-
-try {
-  $phabricator_oauth_uri = new PhutilURI(
-    PhabricatorEnv::getEnvConfig('phabricator.oauth-uri'));
-  $domain_map['phabricator'] = $phabricator_oauth_uri->getDomain();
-} catch (Exception $ex) {
-  // Ignore; this likely indicates that we have removed `phabricator.oauth-uri`
-  // in some future diff.
+foreach (new LiskMigrationIterator($conn, $table_name) as $row) {
+  throw new Exception(
+    pht(
+      'Your Phabricator install has ancient OAuth account data and is '.
+      'too old to upgrade directly to a modern version of Phabricator. '.
+      'Upgrade to a version released between June 2013 and February 2019 '.
+      'first, then upgrade to a modern version.'));
 }
-
-$rows = queryfx_all(
-  $conn_w,
-  'SELECT * FROM user_oauthinfo');
-foreach ($rows as $row) {
-  echo pht('Migrating row ID #%d.', $row['id'])."\n";
-  $user = id(new PhabricatorUser())->loadOneWhere(
-    'id = %d',
-    $row['userID']);
-  if (!$user) {
-    echo pht('Bad user ID!')."\n";
-    continue;
-  }
-
-  $domain = idx($domain_map, $row['oauthProvider']);
-  if (empty($domain)) {
-    echo pht('Unknown OAuth provider!')."\n";
-    continue;
-  }
-
-
-  $xaccount = id(new PhabricatorExternalAccount())
-    ->setUserPHID($user->getPHID())
-    ->setAccountType($row['oauthProvider'])
-    ->setAccountDomain($domain)
-    ->setAccountID($row['oauthUID'])
-    ->setAccountURI($row['accountURI'])
-    ->setUsername($row['accountName'])
-    ->setDateCreated($row['dateCreated']);
-
-  try {
-    $xaccount->save();
-  } catch (Exception $ex) {
-    phlog($ex);
-  }
-}
-
-echo pht('Done.')."\n";
diff --git a/resources/sql/patches/20130611.nukeldap.php b/resources/sql/patches/20130611.nukeldap.php
--- a/resources/sql/patches/20130611.nukeldap.php
+++ b/resources/sql/patches/20130611.nukeldap.php
@@ -1,41 +1,14 @@
 <?php
 
-// NOTE: We aren't using PhabricatorUserLDAPInfo anywhere here because it is
-// being nuked by this change
-
 $table = new PhabricatorUser();
+$conn = $table->establishConnection('w');
 $table_name = 'user_ldapinfo';
-$conn_w = $table->establishConnection('w');
-
-$xaccount = new PhabricatorExternalAccount();
-
-echo pht('Migrating LDAP to %s...', 'ExternalAccount')."\n";
-
-$rows = queryfx_all($conn_w, 'SELECT * FROM %T', $table_name);
-foreach ($rows as $row) {
-  echo pht('Migrating row ID #%d.', $row['id'])."\n";
-  $user = id(new PhabricatorUser())->loadOneWhere(
-    'id = %d',
-    $row['userID']);
-  if (!$user) {
-    echo pht('Bad user ID!')."\n";
-    continue;
-  }
 
-
-  $xaccount = id(new PhabricatorExternalAccount())
-    ->setUserPHID($user->getPHID())
-    ->setAccountType('ldap')
-    ->setAccountDomain('self')
-    ->setAccountID($row['ldapUsername'])
-    ->setUsername($row['ldapUsername'])
-    ->setDateCreated($row['dateCreated']);
-
-  try {
-    $xaccount->save();
-  } catch (Exception $ex) {
-    phlog($ex);
-  }
+foreach (new LiskMigrationIterator($conn, $table_name) as $row) {
+  throw new Exception(
+    pht(
+      'Your Phabricator install has ancient LDAP account data and is '.
+      'too old to upgrade directly to a modern version of Phabricator. '.
+      'Upgrade to a version released between June 2013 and February 2019 '.
+      'first, then upgrade to a modern version.'));
 }
-
-echo pht('Done.')."\n";