code review

Author: bnasslahsen

CHANGELOG.md

@@ -4,6 +4,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.3.9] - 2020-05-05
+### Changed
+- Improved support of spring-boot-1 and older spring versions
+- #647 - Register model converters only if they are not registered already
+### Fixed
+- #646 - Handle NPE on SpringDocAnnotationsUtils.mergeSchema
+
 ## [1.3.8] - 2020-05-04
 ### Added
 - Introduce support of Webflux and Webmvc.fn with Functional Endpoints