*GESA stands for Gateway Esia Software Appliance. Regardless of the hardware, it is based on more or less the same OS (debian or raspbian).
Here is the list of OS used by Esia
⚠️ When upgrading Debian, it is necessary to go through each major intermediate release without skipping any, in order to ensure a stable transition. Example: debian 8 then 9 then 10… ⚠️