HouseRater defaults the OpenStudio analysis version it uses to generate modeling results to the most recent supported version at the time of project creation. However, you are able to change to OpenStudio analysis version, either to a previous version supported prior to project creation or a newer version made available after project creation. To do this:
Open the desired project.
In the results section, select the dropdown next to the "Perform Analysis" button.
From that dropdown, select "Change OpenStudio Version.
A popup will open with a dropdown available. The dropdown will display the currently selected OpenStudio analysis version.
Click the dropdown. You can select your desired OpenStudio analysis version from the list of available versions.
Click the "Save" button to set that version as the active OpenStudio analysis version.