docs: update changelog

CHANGELOG.md

@@ -1,3 +1,16 @@
+### Version 4.38.1 (30th April 2024)
+#### Added
+- Added sending of the additional iOS SDK observability parameters for debugging purposes.
+
+#### Fixed
+- Removed nullability type specifier warnings (https://github.com/adjust/ios_sdk/issues/703).
+
+#### Native SDKs
+- [[email protected]][ios_sdk_v4.38.2]
+- [[email protected]][android_sdk_v4.38.3]
+
+---
+
 ### Version 4.38.0 (27th March 2024)
 #### Added
 - Added iOS Privacy Manifest for the Adjust SDK.
@@ -645,6 +658,7 @@
 [ios_sdk_v4.37.0]: https://github.com/adjust/ios_sdk/tree/v4.37.0
 [ios_sdk_v4.37.2]: https://github.com/adjust/ios_sdk/tree/v4.37.2
 [ios_sdk_v4.38.0]: https://github.com/adjust/ios_sdk/tree/v4.38.0
+[ios_sdk_v4.38.2]: https://github.com/adjust/ios_sdk/tree/v4.38.2
 
 [android_sdk_v4.10.4]: https://github.com/adjust/android_sdk/tree/v4.10.4
 [android_sdk_v4.11.0]: https://github.com/adjust/android_sdk/tree/v4.11.0