diff --git a/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php b/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
index 2605634b2bee..2741a9afd417 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
@@ -33,7 +33,6 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         // doing so also calls setDataLocked(true).
         $builder->setData(isset($options['data']) ? $options['data'] : false);
         $builder->addViewTransformer(new BooleanToStringTransformer($options['value'], $options['false_values']));
-        $builder->setAttribute('_false_is_empty', true); // @internal - A boolean flag to treat false as empty, see Form::isEmpty() - Do not rely on it, it will be removed in Symfony 5.1.
     }
 
     /**
diff --git a/src/Symfony/Component/Form/Form.php b/src/Symfony/Component/Form/Form.php
index adc46ac4fefb..cead4fbd6b27 100644
--- a/src/Symfony/Component/Form/Form.php
+++ b/src/Symfony/Component/Form/Form.php
@@ -740,9 +740,7 @@ public function isEmpty()
             // arrays, countables
             ((\is_array($this->modelData) || $this->modelData instanceof \Countable) && 0 === \count($this->modelData)) ||
             // traversables that are not countable
-            ($this->modelData instanceof \Traversable && 0 === iterator_count($this->modelData)) ||
-            // @internal - Do not rely on it, it will be removed in Symfony 5.1.
-            (false === $this->modelData && $this->config->getAttribute('_false_is_empty'));
+            ($this->modelData instanceof \Traversable && 0 === iterator_count($this->modelData));
     }
 
     /**