I would love to have the History functionality available across all objects in Aha. It exists on most items and is only missing from a handful.
I'm not sure why these were excluded.
The status of this idea was out of date. History is now available on the listed records. History for vision, models, personas, and competitors can be viewed by clicking on the specific component of the record. This will open a drawer that includes a History tab.
I just found out that there IS history on notes, it's just different than history on other items in Aha: https://support.aha.io/hc/en-us/articles/115000533083-Manage-your-product-information-with-notes?mobile_site=true