diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index 880fa0827aa..e2e2a8d94d5 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -101,6 +101,7 @@ class DateField extends TextField
      * to detect invalid values.
      *
      * @var mixed
+     * @deprecated 5.4.0 Use $value instead
      */
     protected $rawValue = null;
 
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 849a0ecb834..5035caea8dc 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -75,6 +75,7 @@ class DatetimeField extends TextField
      * to detect invalid values.
      *
      * @var mixed
+     * @deprecated 5.4.0 Use $value instead
      */
     protected $rawValue = null;
 
diff --git a/src/Forms/FormField.php b/src/Forms/FormField.php
index 77a46ef2c18..209318636dd 100644
--- a/src/Forms/FormField.php
+++ b/src/Forms/FormField.php
@@ -15,6 +15,7 @@
 use SilverStripe\View\AttributesHTML;
 use SilverStripe\View\SSViewer;
 use SilverStripe\View\ViewableData;
+use SilverStripe\Dev\Deprecation;
 
 /**
  * Represents a field in a form.
@@ -1223,9 +1224,11 @@ public function Type()
      * @param bool $result
      * @param Validator $validator
      * @return bool
+     * @deprecated 5.4.0 Use extend() directly instead
      */
     protected function extendValidationResult(bool $result, Validator $validator): bool
     {
+        Deprecation::notice('5.4.0', 'Use extend() directly instead');
         $this->extend('updateValidationResult', $result, $validator);
         return $result;
     }
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index 24ba4645f3d..ffe43821fcc 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -48,6 +48,7 @@ class TimeField extends TextField
      * to detect invalid values.
      *
      * @var mixed
+     * @deprecated 5.4.0 Use $value instead
      */
     protected $rawValue = null;