Elastic is derived from Apache Lucene, it’s unclear if anyone involved in its’ development could legally have made it more restrictive, though they apparently are trying to.

It seems like a lot of us perhaps rushed to discussion before reading this article, which is about Amazon forking ElasticSearch so that an OSS version would remain available.

Honestly, this is a shitty move by Elastic and I’ll be advocating against new uses of it, though /because reasons/, I doubt this will come up for me in the near future. ;)