Upgrade Order for Master/Data/Client Nodes

Elastic Stack Elasticsearch
1

I'm upgrading an existing cluster (v1.3.x to 1.4.x) that has separate master, client and data nodes.

https://www.elastic.co/guide/en/elasticsearch/reference/current/setup-upgrade.html

I know I can do a rolling upgrade, but does the type of node impact the order that I upgrade? For example, should I upgrade all master nodes first?

2

You'd be better off going to 1.6 if you can.

I'd start with masters, then do data, then client.