Older versions of ArcGIS Pro help are eventually archived. When that happens, the content is still available online, but the version switch is removed from topics and a note is added at the top to indicate the content is no longer updated.
Below are links to all versions of ArcGIS Pro help that were available when ArcGIS Pro 2.9 was released, so you can find the help you need, especially if you are using an older version of the software.
- ArcGIS Pro 2.9—https://pro.arcgis.com/en/pro-app/2.9/get-started/get-started.htm
- ArcGIS Pro 2.8—https://pro.arcgis.com/en/pro-app/2.8/get-started/get-started.htm
- ArcGIS Pro 2.7—https://pro.arcgis.com/en/pro-app/2.7/get-started/get-started.htm
- ArcGIS Pro 2.6—https://pro.arcgis.com/en/pro-app/2.6/get-started/get-started.htm
The URLs follow a pattern that includes the version number (for example, /2.7/). You can switch between versions in your browser by changing the version number in the URL and pressing the Enter key. (The most recent version of the help always redirects from the version number to /latest/ so people who want the latest content can easily access it.)
Online help for ArcGIS Pro 2.5 and earlier versions is no longer available. Install the offline help to refer to those versions.