Server - VSTS or TFS on-premises? -> VSTS
Agent - Hosted or Private: -> NA
Visual Studio Test Platform Installer has only an option for the Latest Pre-Release but not for latest release:

@bergmeister the task is still in preview. Right now Latest Pre-Release gets you the latest version (Stable or Preview). We will soon be adding an option for latest Stable also.
But do note that as of today if the latest version available is a stable version then choosing latest pre-release gets you that.
@bergmeister for all intents and purposes latest pre-release == latest release.
These pre-release versions are also thoroughly tested internally.
Also if you are adamant on sticking to a specific stable version then you can use the specific version option.
Ok, thanks, understood. To me it sounds like it would be best to have 3 options:
Latest version (no matter if release or pre-release) as currently present but rrenaming it to Latest version (allow pre-release) or something like that would make it clearer@bergmeister thank you for your feedback. We should picking this up in sometime when we get the task out of preview. @PBoraMSFT to take a look at the suggestion for naming the options.
@ShreyasRmsft This is not how I like open source to be done! No visibility on when the task is in progress or done at all. I find this repo frustrating to work with because issues AND PRs just get closed for reasons like 'not now', 'not interested', 'hard to fix', etc and there is no tags on issues why they are closed...
@bergmeister Apologies. Will keep it open for tracking. The reason is that internally we track all our work items elsewhere and that customers sadly don't have visibility over that. Will take your feedback going forward and keep issues that have pending action items open and tag them appropriately.
Thank you for pointing this out 馃憤
@bergmeister - we have picked this up for execution. Apart from the latest stable / latest including pre-release options, we are also adding support for custom feeds and the task will come out of preview.
ETA for roll-out to all accounts is 3-4 weeks from now.
@ShreyasRmsft - can you close the issue if the deployment rollout has started ?
@PBoraMSFT waiting for it to reach all SUs. Will close after.
@PBoraMSFT Thanks, I can see it already in my VSTS account :-)
Closing the issue.
So....how do I use a custom feed? There's ZERO documentation on this--ANYWHERE.
I selected to use a custom feed and used http://mynugetserver.com/v3/index.json, but acquiring the test tools failed: WARNING: This version of nuget.exe does not support listing packages from source 'http://mynugetserver.com/v3/index.json'.
We're using Azure DevOps Server 2019 (not sure if it's RTM or update 1 or 2) _Update 1_. Task version 1.*.
Please add documentation about what the URL should look like. Also, it might be a good idea to document the minimum version of Nuget.exe that is required and how to go about checking that you meet such a minimum requirement since these tasks are all "black boxes".....
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@bergmeister Apologies. Will keep it open for tracking. The reason is that internally we track all our work items elsewhere and that customers sadly don't have visibility over that. Will take your feedback going forward and keep issues that have pending action items open and tag them appropriately.
Thank you for pointing this out 馃憤