If you purchased MarsEdit 3, you are entitled to a discounted or free upgrade to MarsEdit 4.
Purchases made after June 1, 2017, are entitled to a free upgrade, All other MarsEdit 3 purchasers are entitled to upgrade at a discounted price of $24.95. Licenses for MarsEdit 2 and earlier are not eligible for a a discounted upgrade price.
If you purchased directly from the Red Sweater Store, you can unlock the upgrade after adding MarsEdit 4 to your cart. Just check the “upgrade” box and enter your MarsEdit 3 license information.
If you purchased from the Mac App Store, you can unlock the upgrade from within the Mac App Store version of the app. After you install MarsEdit 4, select Upgrade Pricing… button in the lower right corner of that window., then click the
Thanks for the interest in upgrading. We hope you enjoy MarsEdit 4!