Need ZYXEL NR5101 RG502QEA latest upgrade

Hi everyone
I have the ZYXEL NR5101 NEBULA, Hi, what is the latest and the best Cellular Module Firmware for the ZYXEL NR5101 Nebula? Actualy i have RG502QEAAAR11A03M4G

Regards

Dear @Bjallal
You can try to upgrade via Zyxel.
We have latest firmware, not we don’t test with router, so it is not sure which one is best to router.
If want to try, we can send to you later.