It is possible to sort meeting folders by calendar year. To do that, you need to go to the organization where you want to make the change.
If you want to make the changes in all your organizations, you need to make this change in each individual organization.
Click "Administration" and then "Settings" in the left menu. Then, click the "Advanced Settings" button.
Under the "Meetings" tab, you can set the sorting order for meeting folders by calendar year. Apply the changes by clicking "Save".
Note that the meeting folders remain, but are unlocked if the settings are changed back.
The changes are visible in "Documents" and "All documents" in the left menu. Go into the "Board meetings" folder, where all meetings are stored. Now, your meetings should have been categorized by calendar year.