diff --git a/src/wp-includes/class-wp-text-diff-renderer-table.php b/src/wp-includes/class-wp-text-diff-renderer-table.php
index 0174fed359..b54aa6c368 100644
--- a/src/wp-includes/class-wp-text-diff-renderer-table.php
+++ b/src/wp-includes/class-wp-text-diff-renderer-table.php
@@ -511,35 +511,51 @@ class WP_Text_Diff_Renderer_Table extends Text_Diff_Renderer {
 	 * Make private properties readable for backward compatibility.
 	 *
 	 * @since 4.0.0
+	 * @since 6.4.0 Getting a dynamic property is deprecated.
 	 *
 	 * @param string $name Property to get.
-	 * @return mixed Property.
+	 * @return mixed A declared property's value, else null.
 	 */
 	public function __get( $name ) {
 		if ( in_array( $name, $this->compat_fields, true ) ) {
 			return $this->$name;
 		}
+
+		trigger_error(
+			"The property `{$name}` is not declared. Getting a dynamic property is " .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.',
+			E_USER_DEPRECATED
+		);
+		return null;
 	}
 
 	/**
 	 * Make private properties settable for backward compatibility.
 	 *
 	 * @since 4.0.0
+	 * @since 6.4.0 Setting a dynamic property is deprecated.
 	 *
 	 * @param string $name  Property to check if set.
 	 * @param mixed  $value Property value.
-	 * @return mixed Newly-set property.
 	 */
 	public function __set( $name, $value ) {
 		if ( in_array( $name, $this->compat_fields, true ) ) {
-			return $this->$name = $value;
+			$this->$name = $value;
+			return;
 		}
+
+		trigger_error(
+			"The property `{$name}` is not declared. Setting a dynamic property is " .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.',
+			E_USER_DEPRECATED
+		);
 	}
 
 	/**
 	 * Make private properties checkable for backward compatibility.
 	 *
 	 * @since 4.0.0
+	 * @since 6.4.0 Checking a dynamic property is deprecated.
 	 *
 	 * @param string $name Property to check if set.
 	 * @return bool Whether the property is set.
@@ -548,18 +564,33 @@ class WP_Text_Diff_Renderer_Table extends Text_Diff_Renderer {
 		if ( in_array( $name, $this->compat_fields, true ) ) {
 			return isset( $this->$name );
 		}
+
+		trigger_error(
+			"The property `{$name}` is not declared. Checking `isset()` on a dynamic property " .
+			'is deprecated since version 6.4.0! Instead, declare the property on the class.',
+			E_USER_DEPRECATED
+		);
+		return false;
 	}
 
 	/**
 	 * Make private properties un-settable for backward compatibility.
 	 *
 	 * @since 4.0.0
+	 * @since 6.4.0 Unsetting a dynamic property is deprecated.
 	 *
 	 * @param string $name Property to unset.
 	 */
 	public function __unset( $name ) {
 		if ( in_array( $name, $this->compat_fields, true ) ) {
 			unset( $this->$name );
+			return;
 		}
+
+		trigger_error(
+			"A property `{$name}` is not declared. Unsetting a dynamic property is " .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.',
+			E_USER_DEPRECATED
+		);
 	}
 }
diff --git a/tests/phpunit/tests/diff/wpTextDiffRendererTable.php b/tests/phpunit/tests/diff/wpTextDiffRendererTable.php
new file mode 100644
index 0000000000..4dbbdbbefe
--- /dev/null
+++ b/tests/phpunit/tests/diff/wpTextDiffRendererTable.php
@@ -0,0 +1,161 @@
+<?php
+
+/**
+ * Tests for WP_Text_Diff_Renderer_Table.
+ *
+ * @group diff
+ */
+class Tests_Diff_WpTextDiffRendererTable extends WP_UnitTestCase {
+	/**
+	 * @var WP_Text_Diff_Renderer_Table
+	 */
+	private $diff_renderer_table;
+
+	public static function set_up_before_class() {
+		parent::set_up_before_class();
+		require_once ABSPATH . 'wp-includes/Text/Diff/Renderer.php';
+		require_once ABSPATH . 'wp-includes/class-wp-text-diff-renderer-table.php';
+	}
+
+	public function set_up() {
+		parent::set_up();
+		$this->diff_renderer_table = new WP_Text_Diff_Renderer_Table();
+	}
+
+	/**
+	 * @dataProvider data_compat_fields
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__get()
+	 *
+	 * @param string $property_name Property name to get.
+	 * @param mixed $expected       Expected value.
+	 */
+	public function test_should_get_compat_fields( $property_name, $expected ) {
+		$this->assertSame( $expected, $this->diff_renderer_table->$property_name );
+	}
+
+	/**
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__get()
+	 */
+	public function test_should_throw_deprecation_when_getting_dynamic_property() {
+		$this->expectDeprecation();
+		$this->expectDeprecationMessage(
+			'The property `undeclared_property` is not declared. Getting a dynamic property is ' .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.'
+		);
+		$this->assertNull( $this->diff_renderer_table->undeclared_property, 'Getting a dynamic property should return null from WP_Text_Diff_Renderer_Table::__get()' );
+	}
+
+	/**
+	 * @dataProvider data_compat_fields
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__set()
+	 *
+	 * @param string $property_name Property name to set.
+	 */
+	public function test_should_set_compat_fields( $property_name ) {
+		$value                                     = uniqid();
+		$this->diff_renderer_table->$property_name = $value;
+
+		$this->assertSame( $value, $this->diff_renderer_table->$property_name );
+	}
+
+	/**
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__set()
+	 */
+	public function test_should_throw_deprecation_when_setting_dynamic_property() {
+		$this->expectDeprecation();
+		$this->expectDeprecationMessage(
+			'The property `undeclared_property` is not declared. Setting a dynamic property is ' .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.'
+		);
+		$this->diff_renderer_table->undeclared_property = 'some value';
+	}
+
+	/**
+	 * @dataProvider data_compat_fields
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__isset()
+	 *
+	 * @param string $property_name Property name to check.
+	 * @param mixed $expected       Expected value.
+	 */
+	public function test_should_isset_compat_fields( $property_name, $expected ) {
+		$actual = isset( $this->diff_renderer_table->$property_name );
+		if ( is_null( $expected ) ) {
+			$this->assertFalse( $actual );
+		} else {
+			$this->assertTrue( $actual );
+		}
+	}
+
+	/**
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__isset()
+	 */
+	public function test_should_throw_deprecation_when_isset_of_dynamic_property() {
+		$this->expectDeprecation();
+		$this->expectDeprecationMessage(
+			'The property `undeclared_property` is not declared. Checking `isset()` on a dynamic property ' .
+			'is deprecated since version 6.4.0! Instead, declare the property on the class.'
+		);
+		$this->assertFalse( isset( $this->diff_renderer_table->undeclared_property ), 'Checking a dynamic property should return false from WP_Text_Diff_Renderer_Table::__isset()' );
+	}
+
+	/**
+	 * @dataProvider data_compat_fields
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__unset()
+	 *
+	 * @param string $property_name Property name to unset.
+	 */
+	public function test_should_unset_compat_fields( $property_name ) {
+		unset( $this->diff_renderer_table->$property_name );
+		$this->assertFalse( isset( $this->diff_renderer_table->$property_name ) );
+	}
+
+	/**
+	 * @ticket 58898
+	 *
+	 * @covers WP_Text_Diff_Renderer_Table::__unset()
+	 */
+	public function test_should_throw_deprecation_when_unset_of_dynamic_property() {
+		$this->expectDeprecation();
+		$this->expectDeprecationMessage(
+			'A property `undeclared_property` is not declared. Unsetting a dynamic property is ' .
+			'deprecated since version 6.4.0! Instead, declare the property on the class.'
+		);
+		unset( $this->diff_renderer_table->undeclared_property );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array
+	 */
+	public function data_compat_fields() {
+		return array(
+			'_show_split_view'     => array(
+				'property_name' => '_show_split_view',
+				'expected'      => true,
+			),
+			'inline_diff_renderer' => array(
+				'property_name' => 'inline_diff_renderer',
+				'expected'      => 'WP_Text_Diff_Renderer_inline',
+			),
+			'_diff_threshold'      => array(
+				'property_name' => '_diff_threshold',
+				'expected'      => 0.6,
+			),
+		);
+	}
+}