Comment by herova

Unfortunately, since June 2018, we have witnessed significant intermingling of proprietary code into the code base. While an Apache 2.0 licensed download is still available, there is an extreme lack of clarity as to what customers who care about open source are getting and what they can depend on. For example, neither release notes nor documentation make it clear what is open source and what is proprietary. Enterprise developers may inadvertently apply a fix or enhancement to the proprietary source code. - from amazon's opendistro announcement.