diff --git a/src/aphront/storage/connection/mysql/AphrontBaseMySQLDatabaseConnection.php b/src/aphront/storage/connection/mysql/AphrontBaseMySQLDatabaseConnection.php
--- a/src/aphront/storage/connection/mysql/AphrontBaseMySQLDatabaseConnection.php
+++ b/src/aphront/storage/connection/mysql/AphrontBaseMySQLDatabaseConnection.php
@@ -324,32 +324,15 @@
    * can lead to data loss and security problems.
    */
   protected function validateUTF8String($string) {
-    // TODO: Make this `true` eventually, once we make storage adjustment
-    // mandatory. For now, you can set it to `true` to test things.
-    $has_utf8mb4 = false;
-
-    if ($has_utf8mb4) {
-      if (phutil_is_utf8($string)) {
-        return;
-      }
-
-      throw new AphrontCharacterSetQueryException(
-        pht(
-          'Attempting to construct a query using a non-utf8 string when '.
-          'utf8 is expected. Use the `%%B` conversion to escape binary '.
-          'strings data.'));
-    } else {
-      if (phutil_is_utf8_with_only_bmp_characters($string)) {
-        return;
-      }
-
-      throw new AphrontCharacterSetQueryException(
-        pht(
-          'Attempting to construct a query containing characters outside of '.
-          'the Unicode Basic Multilingual Plane. MySQL will silently truncate '.
-          'this data if it is inserted into a `utf8` column. Use the `%%B` '.
-          'conversion to escape binary strings data.'));
+    if (phutil_is_utf8($string)) {
+      return;
     }
+
+    throw new AphrontCharacterSetQueryException(
+      pht(
+        'Attempting to construct a query using a non-utf8 string when '.
+        'utf8 is expected. Use the `%%B` conversion to escape binary '.
+        'strings data.'));
   }
 
 }