STARS reports and ratings are valid for three years. After that point, a report will still be publicly accessible, but the scores and rating associated with it are removed. If the institution hasn’t submitted a more recent report, the STARS website will list the institution’s rating as “expired” (scroll down the Participants & Reports page for examples).
It is important to note that submitting a report does not immediately result in a new rating. When you submit there will be a review and revision process to complete before the report is published and the new rating is awarded. This can take a month or more, so you will need to budget some time for that if you want to avoid a lapse in rating.
Once an institution publishes a new report, the information and any new rating are updated on the website immediately.