Why am I unable to upload/install Jira Importers Plugin (JIM)

[Jeff Brown]

see previous question: https://community.atlassian.com/t5/Questions/My-user-lacks-the-upload-add-on-link-in-the-UPM/qaq-p/864257#U864261

I managed to enable the ability to 'upload' a mod, but I wasn't given a straight 'upload' control, instead, I had to provide an url.

I tried providing the first version from this page: https://marketplace.atlassian.com/apps/32645/jira-importers-plugin-jim/version-history by right clicking on the download hover link and copying that link to paste in the 'upload' form, which at first seemed to be working, getting the Jar, etc, then through up this error:

https://marketplace.atlassian.com/download/apps/32645/version/368 cannot be installed on this Cloud instance.

Is our jira instance just blocked from using JIM?   Or is there some specific versioning I have to select?  Our whole purpose in using Jira is to get off of bugzilla, and the only sane pathway seems to be using JIM.

[CBE]

Do you use Cloud or Server?

It also took me some time to understand that this page:
https://confluence.atlassian.com/adminjiraserver/migrating-from-other-issue-trackers-938847532.html
is only related to the Server Version of Jira.

When clicking on the "Cloud" Button on the top right of the page to follow to this link:
https://confluence.atlassian.com/adminjiracloud/migrating-from-other-issue-trackers-884344525.html  

there is a yellow box saying

We don't support third-party importers. You must import data into your Jira Cloud site using CSV, JSON, or the Bitbucket or Trello importers.

I think for a "one time migration" it should be possible to use a trial Jira Server instance (e.g. by installing it from https://www.atlassian.com/software/jira/download OR by using docker and this container: https://github.com/cptactionhank/docker-atlassian-jira-software ), doing the import to that instance, exporting the JIRA data and importing that into the cloud, but I didn't try all the steps.