Mongodb upgrade from 3.6 to 4.2 (Splunk 8.2.0 to 9.1.0)

[jcauhape]

I need to upgrade MongoDB from 3.6 to 4.2 as part of the pre-upgrade process for Splunk 8.2.0 to 9.1.0.

So far I have not found a link to a reference which explains how this is done in context of a Splunk installation.

Any clear recommendation is welcome.

[richgalloway]

Instructions for upgrading MongoDB are in the Splunk Admin Manual under "Migrate the KVStore storage engine" at https://docs.splunk.com/Documentation/Splunk/9.1.0/Admin/MigrateKVstore