Just in case you are not aware of, Facebook PHP SDK v3.2.0 has been released on 03Aug. It can be downloaded from the official site.
If we compare the latest vesrion (for which the zip file is marked as facebook-facebook-php-sdk-v3.1.1-76-g98f2be1.zip) to to facebook-php-sdk-v3.1.1-31, we have the following enhancement Items:
- Adding ability to extend tokens
This adds the ability to get extended tokens. Most folks use the JS client-side flow to auth users, which generates a short-lived token. They can now call extendAccessToken() in order to get an long-lived token.
- Providing sharedSession support for better security on shared domains
More information is provided here.