diff --git a/UPGRADE.md b/UPGRADE.md
index 9f80e82c56a..95570e82982 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -730,10 +730,20 @@ The following methods have been removed.
 Relying on the default precision and scale of decimal columns provided by the DBAL is deprecated.
 When declaring decimal columns, specify the precision and scale explicitly.
 
-## Marked `ColumnDiff::hasChanged()` as internal.
+## Marked `Comparator` methods as internal.
 
-The `ColumnDiff::hasChanged()` method has been marked as internal. Use one of the following `ColumnDiff` methods
-in order to check if a given column property has changed:
+The following `Comparator` methods have been marked as internal:
+
+- `columnsEqual()`,
+- `diffForeignKey()`,
+- `diffIndex()`.
+
+The `diffColumn()` method has been deprecated. Use `diffTable()` instead.
+
+## Deprecated `ColumnDiff::$changedProperties` and `::hasChanged()`.
+
+The `ColumnDiff::$changedProperties` property and the `hasChanged()` method have been deprecated. Use one of the
+following `ColumnDiff` methods in order to check if a given column property has changed:
 
 - `hasTypeChanged()`,
 - `hasLengthChanged()`,
diff --git a/psalm.xml.dist b/psalm.xml.dist
index f6e62d924bb..5db2e2b305d 100644
--- a/psalm.xml.dist
+++ b/psalm.xml.dist
@@ -39,8 +39,21 @@
                     See https://github.com/doctrine/dbal/pull/4317
                 -->
                 <file name="tests/Functional/LegacyAPITest.php"/>
+                <!--
+                    TODO: remove in 4.0.0
+                -->
+                <referencedMethod name="Doctrine\DBAL\Schema\ColumnDiff::hasChanged"/>
+                <referencedMethod name="Doctrine\DBAL\Schema\Comparator::diffColumn"/>
             </errorLevel>
         </DeprecatedMethod>
+        <DeprecatedProperty>
+            <errorLevel type="suppress">
+                <!--
+                    TODO: remove in 4.0.0
+                -->
+                <referencedProperty name="Doctrine\DBAL\Schema\ColumnDiff::$changedProperties"/>
+            </errorLevel>
+        </DeprecatedProperty>
         <DocblockTypeContradiction>
             <errorLevel type="suppress">
                 <!--
diff --git a/src/Schema/ColumnDiff.php b/src/Schema/ColumnDiff.php
index d8848e598d6..aca7056a643 100644
--- a/src/Schema/ColumnDiff.php
+++ b/src/Schema/ColumnDiff.php
@@ -18,6 +18,11 @@ class ColumnDiff
      */
     public function __construct(
         public Column $column,
+        /**
+         * @deprecated Use {@see hasTypeChanged()}, {@see hasLengthChanged()}, {@see hasPrecisionChanged()},
+         * {@see hasScaleChanged()}, {@see hasUnsignedChanged()}, {@see hasFixedChanged()}, {@see hasNotNullChanged()},
+         * {@see hasDefaultChanged()}, {@see hasAutoIncrementChanged()} or {@see hasCommentChanged()} instead.
+         */
         public array $changedProperties,
         public Column $fromColumn,
     ) {
@@ -74,7 +79,9 @@ public function hasCommentChanged(): bool
     }
 
     /**
-     * @internal
+     * @deprecated Use {@see hasTypeChanged()}, {@see hasLengthChanged()}, {@see hasPrecisionChanged()},
+     * {@see hasScaleChanged()}, {@see hasUnsignedChanged()}, {@see hasFixedChanged()}, {@see hasNotNullChanged()},
+     * {@see hasDefaultChanged()}, {@see hasAutoIncrementChanged()} or {@see hasCommentChanged()} instead.
      */
     public function hasChanged(string $propertyName): bool
     {
diff --git a/src/Schema/Comparator.php b/src/Schema/Comparator.php
index fb9c3952079..6ec0f3d1c73 100644
--- a/src/Schema/Comparator.php
+++ b/src/Schema/Comparator.php
@@ -7,6 +7,7 @@
 use Doctrine\DBAL\Exception;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types;
+use Doctrine\Deprecations\Deprecation;
 
 use function array_intersect_key;
 use function array_keys;
@@ -381,6 +382,9 @@ private function detectIndexRenamings(TableDiff $tableDifferences): void
         }
     }
 
+    /**
+     * @internal The method should be only used from within the {@see Comparator} class hierarchy.
+     */
     public function diffForeignKey(ForeignKeyConstraint $key1, ForeignKeyConstraint $key2): bool
     {
         if (
@@ -411,6 +415,8 @@ public function diffForeignKey(ForeignKeyConstraint $key1, ForeignKeyConstraint
     /**
      * Compares the definitions of the given columns
      *
+     * @internal The method should be only used from within the {@see Comparator} class hierarchy.
+     *
      * @throws Exception
      */
     public function columnsEqual(Column $column1, Column $column2): bool
@@ -424,10 +430,19 @@ public function columnsEqual(Column $column1, Column $column2): bool
      * If there are differences this method returns the changed properties as a
      * string array, otherwise an empty array gets returned.
      *
+     * @deprecated Use {@see diffTable()} instead.
+     *
      * @return array<int, string>
      */
     public function diffColumn(Column $column1, Column $column2): array
     {
+        Deprecation::triggerIfCalledFromOutside(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/5650',
+            '%s is deprecated. Use diffTable() instead.',
+            __METHOD__,
+        );
+
         $properties1 = $column1->toArray();
         $properties2 = $column2->toArray();
 
@@ -507,6 +522,8 @@ public function diffColumn(Column $column1, Column $column2): array
      *
      * Compares $index1 with $index2 and returns $index2 if there are any
      * differences or false in case there are no differences.
+     *
+     * @internal The method should be only used from within the {@see Comparator} class hierarchy.
      */
     public function diffIndex(Index $index1, Index $index2): bool
     {