We are currently working on creating an Elasticsearch deployment of around 350 Data Nodes, running on 70 physical servers (each server hosting 5 Nodes).
The cluster isn't in production yet, the app is still in development.
Currently we are developing based on Elasticsearch 6.2.4, but we have the option of using ES 6.3.1 instead (not any version more recent because of inner technical difficulties).
Since switching to 6.3.1 might cost us significant time in changing code and testing, I would like to ask:
Is there any known major issue in 6.2.4 that is solved in 6.3.1? Especially in regard to very large clusters.
I have read through the issues on Github and was unable to figure out whether the issues solved are crucial / relevant to our project or not.