After completing the updates, you still need to download the latest phpBB package from the downloads page.
Then, run the update file and schemas which will make appropriate modifications as needed to your database from that pack. It will update the version # for you.
FYI, the version # is stored in your phpbb_config database table (replace phpbb_ with your table prefix). But, it's best to use the update files to do it as each upgrade may have made changes to the database as well.