From our coding session this past weekend, the coding is for the i3 to "recognize" more than 1.9 gallons. You can pump 2.4 gals, but the REX will only use 1.9 G - you'll be left with 0.5 gal in the tank.
There are two separate items here. The tokens generated by the E-Sys Launcher each time you fire it up. There's also a separate "activation" code that's delivered by TokenMaster who's the dev for the app. You need the activation code to install E-Sys Launcher.