<link>http://hamcrest.org/JavaHamcrest/javadoc/2.2/</link>
<link>http://www.slf4j.org/apidocs/</link>
<link>https://google.github.io/guava/releases/31.1-jre/api/docs/</link>
- <link>http://doc.akka.io/japi/akka/2.6.19/</link>
+ <link>http://doc.akka.io/japi/akka/2.6.20/</link>
<link>http://netty.io/4.1/api/</link>
<link>https://commons.apache.org/proper/commons-lang/javadocs/api-release/</link>