Validating Current Environment is ready for 9.0 Upgrade

[scout29]

We are in the process of upgrading our 8.2.6 Splunk distributed environment to 9.1.0

I would like to ensure that all of our apps and add-ons are 9.1 compatible (and make sure this is no python 2 code) - is there a SPL search i can run that can help me identify apps or add-ons that need to be upgraded? I have installed the readiness app, however it doesn't seem to capture all of our apps and add-ons in the environment.  

[FelixLeh]

Depening on how many Apps are disregarded by the Readiness App you could check the Outlier Apps on Splunkbase. If your currently installed version supports Splunk 9.x it should support Python 3 as well.

A note regarding 9.x Upgrades:
While upgrading to 9.x  from 8.x or lower; check how much storage your KV Stores take up on your systems. The KV Storage gets upgraded in the process of the Update and Splunk wants to backup all Kvstores in the process. This requires at least twice the amount of storage your KVStores currently use. If you don't do so you have to manually upgrade them afterwards instead of as part of the Splunk Upgrade Process.