diff --git a/includes/update.inc b/includes/update.inc
index 1eb7a1d..8c5db98 100644
--- a/includes/update.inc
+++ b/includes/update.inc
@@ -178,6 +178,14 @@ function update_prepare_d7_bootstrap() {
       $_COOKIE[session_name()] = $sid;
       session_id($sid);
     }
+
+    // Upgrading from D6 to D7.{0,1,2,3,4,8,...} is different than upgrading
+    // from D6 to D7.{5,6,7} which should be considered broken. To be able to
+    // properly handle this difference in node_update_7012 we need to keep track
+    // of whether a D6 > D7 upgrade or a D7 > D7 update is running.
+    // Since variable_set() is not available here, the D6 status is being saved
+    // in a local variable to be able to store it later.
+    $update_d6 = TRUE;
   }
 
   // Create the registry tables.
@@ -302,6 +310,11 @@ function update_prepare_d7_bootstrap() {
     // Set the timezone for this request only.
     $GLOBALS['conf']['date_default_timezone'] = 'UTC';
   }
+
+  // This allows update functions to tell if an upgrade from D6 is running.
+  if (!empty($update_d6)) {
+    variable_set('update_d6', TRUE);
+  }
 }
 
 /**
@@ -1069,6 +1082,10 @@ function update_batch($start, $redirect = NULL, $url = NULL, $batch = array(), $
  * @see update_batch()
  */
 function update_finished($success, $results, $operations) {
+  // Remove the D6 upgrade flag variable so that subsequent update runs do not
+  // get the wrong context.
+  variable_del('update_d6');
+
   // Clear the caches in case the data has been updated.
   drupal_flush_all_caches();
 
diff --git a/modules/node/node.install b/modules/node/node.install
index d33f095..a1f77bb 100644
--- a/modules/node/node.install
+++ b/modules/node/node.install
@@ -616,6 +616,7 @@ function node_update_7006(&$sandbox) {
       'module' => 'text',
       'cardinality' => 1,
       'entity_types' => array('node'),
+      'translatable' => TRUE,
     );
     _update_7000_field_create_field($body_field);
 
@@ -867,5 +868,37 @@ function node_update_7011() {
 }
 
 /**
+ * Switches body fields to untranslatable while upgrading from D6 and makes them language neutral.
+ */
+function node_update_7012() {
+  // If we are upgrading from D6, then body fields should be set back to
+  // untranslatable, as D6 did not know about the idea of translating fields,
+  // but only nodes. If a D7 > D7 update is running we need to skip this update,
+  // as it is a valid use case to have translatable body fields in this context.
+  if (variable_get('update_d6', FALSE)) {
+    // Make node bodies untranslatable: field_update_field() cannot be used
+    // throughout the upgrade process and we do not have an update counterpart
+    // for _update_7000_field_create_field(). Hence we are forced to update the
+    // 'field_config' table directly. This is a safe operation since it is
+    // being performed while upgrading from D6. Perfoming the same operation
+    // during a D7 update is highly discouraged.
+    db_update('field_config')
+      ->fields(array('translatable' => 0))
+      ->condition('field_name', 'body')
+      ->execute();
+
+    // Switch field languages to LANGUAGE_NONE, since initially they were
+    // assigned $node->language.
+    foreach (array('field_data_body', 'field_revision_body') as $table) {
+      db_update($table)
+        ->fields(array('language' => LANGUAGE_NONE))
+        ->execute();
+    }
+
+    node_type_cache_reset();
+  }
+}
+
+/**
  * @} End of "addtogroup updates-6.x-to-7.x"
  */
diff --git a/modules/simpletest/simpletest.info b/modules/simpletest/simpletest.info
index f51804c..6b5f34d 100644
--- a/modules/simpletest/simpletest.info
+++ b/modules/simpletest/simpletest.info
@@ -45,5 +45,6 @@ files[] = tests/upgrade/upgrade.locale.test
 files[] = tests/upgrade/upgrade.menu.test
 files[] = tests/upgrade/upgrade.node.test
 files[] = tests/upgrade/upgrade.taxonomy.test
+files[] = tests/upgrade/upgrade.translatable.test
 files[] = tests/upgrade/upgrade.upload.test
 files[] = tests/upgrade/upgrade.user.test
diff --git a/modules/simpletest/tests/upgrade/drupal-6.translatable.database.php b/modules/simpletest/tests/upgrade/drupal-6.translatable.database.php
new file mode 100644
index 0000000..5162116
--- /dev/null
+++ b/modules/simpletest/tests/upgrade/drupal-6.translatable.database.php
@@ -0,0 +1,125 @@
+<?php
+
+/**
+ * Database additions for translatable tests.
+ */
+
+db_insert('node')->fields(array(
+  'nid',
+  'vid',
+  'type',
+  'language',
+  'title',
+  'uid',
+  'status',
+  'created',
+  'changed',
+  'comment',
+  'promote',
+  'moderate',
+  'sticky',
+  'tnid',
+  'translate',
+))
+->values(array(
+  'nid' => '53',
+  'vid' => '63',
+  'type' => 'translatable_page',
+  'language' => 'fr',
+  'title' => 'First translatable page',
+  'uid' => '1',
+  'status' => '1',
+  'created' => '1298363952',
+  'changed' => '1298363952',
+  'comment' => '2',
+  'promote' => '0',
+  'moderate' => '0',
+  'sticky' => '0',
+  'tnid' => '0',
+  'translate' => '0',
+))
+->execute();
+
+db_insert('node_revisions')->fields(array(
+  'nid',
+  'vid',
+  'uid',
+  'title',
+  'body',
+  'teaser',
+  'log',
+  'timestamp',
+  'format',
+))
+->values(array(
+  'nid' => '53',
+  'vid' => '63',
+  'uid' => '1',
+  'title' => 'First translatable page',
+  'body' => 'Body of the first translatable page.',
+  'teaser' => 'Teaser of the first translatable page.',
+  'log' => '',
+  'timestamp' => '1298363952',
+  'format' => '1',
+))
+->execute();
+
+db_insert('node_comment_statistics')->fields(array(
+  'nid',
+  'last_comment_timestamp',
+  'last_comment_name',
+  'last_comment_uid',
+  'comment_count',
+))
+->values(array(
+  'nid' => '53',
+  'last_comment_timestamp' => '1298363952',
+  'last_comment_name' => NULL,
+  'last_comment_uid' => '1',
+  'comment_count' => '0',
+))
+->execute();
+
+db_insert('node_type')->fields(array(
+  'type',
+  'name',
+  'module',
+  'description',
+  'help',
+  'has_title',
+  'title_label',
+  'has_body',
+  'body_label',
+  'min_word_count',
+  'custom',
+  'modified',
+  'locked',
+  'orig_type',
+))
+->values(array(
+  'type' => 'translatable_page',
+  'name' => 'Translatable page',
+  'module' => 'node',
+  'description' => 'A <em>translatable page</em> is like a normal page, but with multilanguage support.',
+  'help' => '',
+  'has_title' => '1',
+  'title_label' => 'Title',
+  'has_body' => '1',
+  'body_label' => 'Body',
+  'min_word_count' => '0',
+  'custom' => '0',
+  'modified' => '0',
+  'locked' => '1',
+  'orig_type' => '',
+))
+->execute();
+
+db_insert('variable')->fields(array(
+  'name',
+  'value',
+))
+->values(array(
+  'name' => 'language_content_type_translatable_page',
+  'value' => 's:1:"1";',
+))
+->execute();
diff --git a/modules/simpletest/tests/upgrade/upgrade.test b/modules/simpletest/tests/upgrade/upgrade.test
index 8a3da81..6aadee3 100644
--- a/modules/simpletest/tests/upgrade/upgrade.test
+++ b/modules/simpletest/tests/upgrade/upgrade.test
@@ -402,5 +402,9 @@ class BasicUpgradePath extends UpgradePathTestCase {
     // Confirm that no {menu_links} entry exists for user/autocomplete.
     $result = db_query('SELECT COUNT(*) FROM {menu_links} WHERE link_path = :user_autocomplete', array(':user_autocomplete' => 'user/autocomplete'))->fetchField();
     $this->assertFalse($result, t('No {menu_links} entry exists for user/autocomplete'));
+
+    // Test that the environment after the upgrade is in a consistent status.
+    $update_d6 = variable_get('update_d6', FALSE);
+    $this->assertFalse($update_d6, t('The D6 upgrade flag variable has been correctly disabled.'));
   }
 }
diff --git a/modules/simpletest/tests/upgrade/upgrade.translatable.test b/modules/simpletest/tests/upgrade/upgrade.translatable.test
new file mode 100644
index 0000000..c9360f3
--- /dev/null
+++ b/modules/simpletest/tests/upgrade/upgrade.translatable.test
@@ -0,0 +1,51 @@
+<?php
+
+/**
+ * Upgrade test for translatable content types of node.module.
+ */
+class TranslatableUpgradePathTestCase extends UpgradePathTestCase {
+  public static function getInfo() {
+    return array(
+      'name'  => 'Translatable content upgrade path',
+      'description'  => 'Upgrade path tests for the translatable content types of Node module.',
+      'group' => 'Upgrade path',
+    );
+  }
+
+  public function setUp() {
+    // Path to the database dump files.
+    $this->databaseDumpFiles = array(
+      drupal_get_path('module', 'simpletest') . '/tests/upgrade/drupal-6.filled.database.php',
+      drupal_get_path('module', 'simpletest') . '/tests/upgrade/drupal-6.locale.database.php',
+      drupal_get_path('module', 'simpletest') . '/tests/upgrade/drupal-6.translatable.database.php',
+    );
+    parent::setUp();
+
+    $this->uninstallModulesExcept(array('locale'));
+  }
+
+  /**
+   * Test a successful upgrade (no negotiation).
+   */
+  public function testTranslatableUpgrade() {
+    $this->assertTrue($this->performUpgrade(), t('The upgrade was completed successfully.'));
+
+    // The D6 database contains the english node "First translatable page" with
+    // nid 53.
+    $nid = 53;
+    $title = 'First translatable page';
+    $teaser = 'Teaser of the first translatable page.';
+    $body = 'Body of the first translatable page.';
+
+    // Check whether the node displays properly.
+    $this->drupalGet("node/$nid");
+    $this->assertText($body, t('Translatable node body displays properly'));
+
+    // Retrieve node object, ensure that both the body and the teaser has
+    // survived upgrade properly.
+    $node = $this->drupalGetNodeByTitle($title);
+    $this->assertTrue($node != NULL, t('Node @title was loaded', array('@title' => $title)));
+    $this->assertEqual($node->body[LANGUAGE_NONE][0]['value'], $body, 'Body of the node survived upgrade properly');
+    $this->assertEqual($node->body[LANGUAGE_NONE][0]['summary'], $teaser, 'Teaser of the node survived upgrade properly');
+  }
+}