Mellel 3.5.3 is Here... (May 17, 2017)
But your version of Mellel is not up to date
The current version of Mellel is 3.5.3 The version you have installed is Mellel 2.6 or earlier.
Mellel 3.5.3 is a bug fix release to Mellel 3.5, a major update to Mellel, including various new features, enhancements and bug fixes. To learn about the new features in Mellel, see Here.
Important: Mellel 3.5.3 is a free update for anyone who've purchased Mellel after December 2007. If you've purchased Mellel before December 2007, you'll need to purchase an update to upgrade to the latest version of Mellel.