[Apiman-user] ES version supported in Apiman 1.5.1 final.

Hello, I am upgrading to latest Apiman 1.5.1 release from 1.3.x version. I noticed the ES is now migrated to 5.x (thanks for this change). But If I look in to ES product, the latest version is 6.x since early 2018. Is there any reason that Apiman can support only 5.x version ? I can think of one reason that embedded Jest client jar is 5.x version which makes it supported by ES 5.x version only ? Thanks Balu