EasyDiscuss: help to upgrade from Version: 3.1.8683 tp Current Version

Hi,

1. My Joomla version is 2.5.14; and my Easydiscuss Version: 3.1.8683. I want to upgrade my site to current versions. which one should I upgrade first, Joomla or Easydiscuss?

2. I have missed several version after Version: 3.1.8683 (Easydiscuss). Can I directly upgrade to current version or should I upgrade to a relatively lower version first and then to the current version?

Thanks.