From 83021c592e3656622c6d8ada91fddd0895ec8fdb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Tamarelle?=
 <jerome.tamarelle@mongodb.com>
Date: Fri, 11 Apr 2025 09:14:07 +0200
Subject: [PATCH] Mention Serializable/Unserializable types in upgrade guide
 (#1805)

---
 UPGRADE-2.0.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/UPGRADE-2.0.md b/UPGRADE-2.0.md
index 534c8f126..71d2eff89 100644
--- a/UPGRADE-2.0.md
+++ b/UPGRADE-2.0.md
@@ -1,6 +1,10 @@
 UPGRADE FROM 1.x to 2.0
 =======================
 
+ * Add return type to implementations of `MongoDB\BSON\Serializable::bsonSerialize()`,
+   with `array|\stdClass|Document|PackedArray` or a subset of this union type.
+ * Add parameter and return type to implementations of `MongoDB\BSON\Unserializable`
+   to comply with the `bsonUnserialize(array $data): void` signature.
  * The `getServer()` method has been removed from the CommandFailedEvent,
    CommandStartedEvent, and CommandSucceededEvent event classes. The `getHost()`
    and `getPort()` methods have been added in its place.