Elasticsearch Integration - unavailable?

I'm building a monitoring cluster built on an 8.1.1 stack and I noticed that the Elasticsearch integration for Agent isn't available but it is available on an older 7.17 stack.
Elasticsearch integration docs

This integration is really important to our monitoring strategy, we can gather the data with Beats but we're looking for Fleet control, so running two monitoring solutions in parallel is a bit of a deal breaker for us.

So my questions are; which versions of the stack have the Elasticsearch agent integration available ?
Or, is there a way to get this integration installed and working with an 8.1.1 stack ?

That page mentions;

The elasticsearch package can monitor Elasticsearch 6.7.0 and later.

So 7.17 should be fine?

Yes, but my monitoring stack is on 8.1.1 do I have to downgrade to 7.17 in order to use it ?
I need to know which versions of the stack it's available for so that I can pick the one that's best for us, there's some features under 8.x I don't want to lose.
Is this not recorded anywhere ? If not, is there anyway that I can tell which versions it'll work for ? Would it be in the code ?

I am not following you sorry. The docs mention it can handled anything above 6.7, which includes 7.17 and 8.1

Yes, Elastic Stack monitoring related integrations with Elastic Agent, i.e. Elasticsearch, Kibana, and Logstash, are not ready for version 8 yet. They can only be used in version 7.
If you have installed the integration in version 7, and then upgraded to version 8, you should still be able to continue using the integrations.

Ah thank you. Is there a timeline for the Agent integrations to be added to 8.x or is the strategy to go back to just using Beats again ?

My monitoring stack is running 8.1, along with Agent, Fleet Command etc
We monitor a variety of production stacks here.
I noticed that the Elasticsearch Integration for Agent wasn't available for deployment from my 8.1 stack.
But I was playing with one of our production 7.17 stacks and by chance I noticed the Elasticsearch Integration for Agent was available for deployment from that stack.
So my question is, what's the latest version of the stack I should use to (re)build my monitoring cluster where I can use it to deploy and control the Elasticsearch Integration for Agent ?

You can use the latest version 7 if you prefer to use Elastic Agent integration for your Elastic Stack monitoring.

If you browse through GitHub, there are various enhancements that are being implemented to the integration so that they can be released as GA in version 8.x.

Sadly this didn't work. I installed a basic 7.17 stack, 1 ES node and 1 kibana, and installed the elasticsearch integration. I shutdown ES and kibana and ran an "apt upgrade" (I'm on ubuntu).
ES and kibana both upgraded to 8.4.1 but the integration wasn't there. It wasn't listed as installed or available to be installed.

You won't be able to see the integration in 8.x. However, you should be able to add the integration that you have installed into your agent policy.