Doesn't appear to be earth shattering changes. In fact it looks pretty boilerplate.

As someone who maintains an Elasticsearch plugin, you often have to do A LOT of research into how Elastic themselves have dealt with their undocumented, constantly evolving APIs to figure out how to adapt your own code. Stuff like this happens all the time where some boilerplate code changes, you copy in the way Elastic themselves did it. Given how the code is now a mix of Elastic and Apache code, now you can create a host of legal liability by accidentally taking the wrong piece of boilerplate.

Potential legal liability on top the headaches of maintaining an open source project in my spare time with almost no support. Oh joy.