There are breaking changes, but none seem to hit Deichman's usage. The changes in the config is to avoid warnings. The discovery-type is a security measure.
The code was tested locally and a full reindexing was done with good results.
As a part of the release, me and Petter have discussed doing a "clean slate" reindexing to try to get the production index in sync. This means that we can safely deploy this code, but we should do reindexing the same evening. NOTE: this procedure should be done in the test environment first!
TRUNCATE sibyl.index_docs and
TRUNCATE sibyl.koha_cache in Sibyl's DB
docker volume rm deichman_elasticsearch_data)