If you are in latest Sage X3 v12 (Patch 33; 2023R1), then ElasticSearch installation can be optional (read: not a required installation).

You will lose out on the magnifying glass search feature to find for specific record but if you never used it and never schedule daily cache update, no loss anyway.

If you need, it must be ElasticSearch 7: https://online-help.sageerpx3.com/erp/12/public/getting-started_sage-erp-x3-installation-procedure.html#elastic 

I would recommend just throwing away the whole old thing and rebuild the whole cache from clean state.

Thanks chunheng. I was looking at this and noticed that it says I should install it before the Syracuse install. Since I'm already running with 2022R4 and not updating to 2023R1 for a while yet, do you know if ditching it and rebuilding it now is an issue? I did do some other research on the ElasticSearch site and see that I can run the upgrade path of 0.90 to 2.4 using the process for a full cluster restart, 2.4 to 5.6 as well, and then 5.6 to 6.8 and 6.8 to 7.16 using Rolling upgrades. Would there be anything special in the handling of it with X3 that I would need to know about?

If you are only using Elastic Search for X3, then there is not much advantage in keeping the elastic search data as this can easily be recreated by running a full re-index. i.e. you can simply remove the old Elastic Search and install the latest certified one.    Refer to my KB article https://gb-kb.sage.com/portal/app/portlets/results/viewsolution.jsp?solutionid=225924850099424 for more information.

Hope this helps