diff --git a/validation/custom_constraint.rst b/validation/custom_constraint.rst
index b946901c6f8..f4f81294c38 100644
--- a/validation/custom_constraint.rst
+++ b/validation/custom_constraint.rst
@@ -66,7 +66,7 @@ The validator class is also simple, and only has one required method ``validate(
         public function validate($value, Constraint $constraint)
         {
             if (!$constraint instanceof ContainsAlphanumeric) {
-               throw new UnexpectedTypeException($constraint, ContainsAlphanumeric::class);
+                throw new UnexpectedTypeException($constraint, ContainsAlphanumeric::class);
             }
             
             // custom constraints should ignore null and empty values to allow
@@ -76,7 +76,11 @@ The validator class is also simple, and only has one required method ``validate(
             }
 
             if (!is_string($value)) {
-                throw new UnexpectedTypeException($value, 'string');
+                // throw this exception if your validator cannot handle the passed type so that it can be marked as invalid
+                throw new UnexpectedValueException($value, 'string');
+
+                // separate multiple types using pipes
+                // throw new UnexpectedValueException($value, 'string|int');
             }
 
             if (!preg_match('/^[a-zA-Z0-9]+$/', $value, $matches)) {
@@ -94,6 +98,9 @@ message as its argument and returns an instance of
 :class:`Symfony\\Component\\Validator\\Violation\\ConstraintViolationBuilderInterface`.
 The ``addViolation()`` method call finally adds the violation to the context.
 
+.. versionadded:: 4.2
+    The ``UnexpectedValueException`` was introduced in Symfony 4.2.
+
 Using the new Validator
 -----------------------