CHANGELOG.md in logstash-output-email-3.0.5 vs CHANGELOG.md in logstash-output-email-4.0.0

@@ -1,4 +1,6 @@
+## 4.0.0
+  - Update the plugin to the version 2.0 of the plugin api, this change is required for Logstash 5.0 compatibility. See https://github.com/elastic/logstash/issues/5141
 # 3.0.5
   - Depend on logstash-core-plugin-api instead of logstash-core, removing the need to mass update plugins on major releases of logstash
 # 3.0.4
   - Set the version of Mail to 2.6.3, since 2.6.4 has a dependency incompatible with jruby see https://github.com/elastic/logstash/issues/4883