The invention is a method of updating a first executable code comprised in a first package in a secure element, a class instance being instantiated from said first package and comprising instance data. The method comprises the following steps: loading in the secure element an upgrade file comprising a second executable code and creating a second package from said upgrade file, changing said first executable code for said second executable code by replacing a reference to the first package by a reference to the second package in a package list stored in the secure element, while leaving the class instance alive and said instance data unchanged.