We are using an old version of Elastic Stack (Elasticsearch, Logstash, Filebeat and Kibana) that we wanted to upgrade to lastest version (6.7) released yesterday (26/03). But we were wondering if we wouldn't wait for the version 7 except that we noticed this: Elasticsearch 7.0 can read indices created in version 6.0 or above. An Elasticsearch 7.0 node will not start in the presence of indices created in a version of Elasticsearch before 6.0.
As this is a little ambiguous (it doesn't explicitly says that Elasticsearch 7.0 won't be able to write on an ELasticsearch 6.x index for example and if reindexing for a version before 6.x to an Elasticsearch 7.0 won't be acceptable) my question is... what is the best solution to upgrade?
Will it be possible to mount a cluster of Elasticsearch 7 nodes and use remote cluster reindex to reindex our indices from version 5.5 to the Elasticsearch 7 node?
P.S: when will the Elasticsearch 7 be released?