Elasticsearch will changes a license to SSPL or Elastic license, so it’s not OSS license… But we want to continue to provide Fess under Apache license! Therefore, we decide to replace a default engine in Fess with Fesen. Fesen is a product forked from Elasticsearch. We believe this change does not affect Fess users.
For Fess users
No changes! You can use Fess with Elasticsearch, and Fess will support a future version of Elasticsearch. So, many users will not notice this change.
For Fess developers
The problem of the license change will affect us because Fess uses and contains libraries of Elasticsearch. This dependency means Fess needs to change Apache license to SSPL. Moreover, we cannot create several libraries, such as elasticsearch-cluster-runner, which depends on Elasticsearch libraries. Therefore, we need to develop our search engine and replace Elasticsearch with Fesen to avoid the license problem.
This replacement is an internal change. Fess users can also use Fess with Elasticsearch in future releases.