Compatibility question

[Bruce_Zu]

Hi, guys,
Excuse me, I have a question about compatibility
I want to know if my current code, based on version 6.8, workable with 7.17 cluster.
Some of our cluster has been upgraded from 6.8 to 7.17.

On the client side, We use version 6.8 high level Java client API.
If it is workable with the new cluster 7.17, then we do not need to upgrade or prepare a new set of customized Client based on the new JAVA API provided by 7.17

I have read the following 2 links, but no explicitly answer there.

Compatibility | Java REST Client [7.17] | Elastic

Compatibility | Java REST Client [6.8] | Elastic

From the link Upgrading the Elastic Stack | Installation and Upgrade Guide [7.17] | Elastic
it is said " The Java High Level REST Client can communicate with any Elasticsearch node running the same major version and greater or equal minor version. When you upgrade to the next major version, the client should be updated after all of the nodes in the cluster have been updated."

But it does not say whether the High level Java client with major version 6.x, e.g. 6.8.0, will work with cluster with major version 7.x, e.g. 7.17.

Thank you!
Bruce

[swallez (Sylvain Wallez)]

The High level Java client version 6.8.x is likely to "mostly" work with cluster version 7.x. It depends on the APIs you are using: some APIs that were deprecated in 6.x have been removed in 7.x, and those APIs will not work anymore.

[Bruce_Zu]

@swallez Hi Swallez, thank you so much for shedding light here. We will test case by case, anyway it is glad to find "'mostly' works"