The licence granted for using the e-course does not have a time limit. It will remain valid for as long as it is used on a compatible device for which it has been tested, validated and sold.
The licence will remain in force for the legal duration of the copyright and intellectual property rights held by ASSIMIL for the app. (However, the licence will be immediately withdrawn should the user fail to comply with the T&Cs  stipulated in Section 5.2).