This summer we moved some of our older articles to our docs-archive repository. We want to continue to help you troubleshoot issues on older versions of our products, but make it easier for you to find newer content on the Support Portal. You can always find documentation for our newer, supported products on our docs site and here at the Support Portal.
At our archive, you'll find an easy to navigate list of articles that covers only Puppet Enterprise versions earlier than 2018.1. If you can't find an older article there, it might still be here; some of the articles at the Support Portal cover older versions of PE (but also include newer versions).
We chose to hang on to articles for the most recent end of life LTS version of PE, since we'd like to help you move to supported versions of our products. As versions (and products) end of life, we anticipate adding more articles to the archive in the future.