diff --git a/core/modules/locale/locale.post_update.php b/core/modules/locale/locale.post_update.php
new file mode 100644
index 0000000000..91728f305e
--- /dev/null
+++ b/core/modules/locale/locale.post_update.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * @file
+ * Post-update functions for Locale module.
+ */
+
+/**
+ * Clear cache to ensure translations with old style are clear.
+ */
+function locale_post_update_clear_cache_for_old_translations() {
+  // Remove cache of translations, like '@count[2] words'.
+}
diff --git a/core/modules/locale/src/LocaleLookup.php b/core/modules/locale/src/LocaleLookup.php
index 9290efc305..80dc134052 100644
--- a/core/modules/locale/src/LocaleLookup.php
+++ b/core/modules/locale/src/LocaleLookup.php
@@ -172,6 +172,11 @@ protected function resolveCacheMiss($offset) {
       }
     }
 
+    if (is_string($value)) {
+      // Fix old style plural problem, when value contains @count[number].
+      $value = preg_replace('!@count\[\d+\]!', '@count', $value);
+    }
+
     $this->storage[$offset] = $value;
     // Disabling the usage of string caching allows a module to watch for
     // the exact list of strings used on a page. From a performance
diff --git a/core/modules/locale/tests/src/Functional/LocaleLocaleLookupTest.php b/core/modules/locale/tests/src/Functional/LocaleLocaleLookupTest.php
index 5f3e5f7e80..3d2cca417e 100644
--- a/core/modules/locale/tests/src/Functional/LocaleLocaleLookupTest.php
+++ b/core/modules/locale/tests/src/Functional/LocaleLocaleLookupTest.php
@@ -4,6 +4,7 @@
 
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\Core\Cache\CacheCollectorHelper;
 
 /**
  * Tests LocaleLookup.
@@ -55,4 +56,38 @@ public function testLanguageFallbackDefaults() {
     $this->assertEqual($context['operation'], 'locale_lookup');
   }
 
+  /**
+   * Test old plural style @count[number] fix.
+   */
+  public function testFixOldPluralStyle() {
+    /** @var \Drupal\locale\StringDatabaseStorage $string_storage */
+    $string_storage = \Drupal::service('locale.storage');
+
+    $string = $string_storage->findString(['source' => 'Member for', 'context' => '']);
+
+    // Create translation with old @count[2] plural style.
+    $string_storage->createTranslation([
+      'lid' => $string->getId(),
+      'language' => 'fr',
+      'translation' => '@count[2] old-plural-test',
+    ])->save();
+
+    // Assert that @count[2] was fixed with caching.
+    drupal_flush_all_caches();
+    $this->drupalGet('');
+    $this->assertSession()->pageTextContains('@count old-plural-test');
+
+    // Assert that @count[2] wasn't fixed after caching.
+    drupal_flush_all_caches();
+    $collector = new CacheCollectorHelper('locale:fr::authenticated', $this->container->get('cache.default'), $this->container->get('lock'));
+    $collector->set('Member for', '@count[2] old-plural back');
+    $collector->destruct();
+    $this->drupalGet('');
+    $this->assertSession()->pageTextContains('@count[2] old-plural back');
+
+    // Assert that source not changed.
+    $translation = $string_storage->findTranslation(['language' => 'fr', 'lid' => $string->getId()])->translation;
+    $this->assertSame('@count[2] old-plural-test', $translation);
+  }
+
 }