After 18 months flying with my P4P, i've never updated the bird itself.  Never had any problems flying it.  So should i update or not through DJI assit 2 ??   Could the drone benefit of more functionalities if i do or will it start doing crazy things up in the air ?

Hi there, thank you for reaching out and we really admire you being interested in the Product. With regards to that update each update has an optimization and added the feature as well, you may check this release notes for each update. https://dl.djicdn.com/downloads/ ... elease_Notes_EN.pdf Thank you for your support.

It's a roll of the dice!

What version of firmware are you running

“To update or not...”
NOT!
Only two reasons to upgrade/update any software/firmware on any device.

1. Doing so will give you features or capabilities you want or need and do not currently have.

2. Doing so will correct a problem you are currently experiencing.

Based on your post neater apply to you. My opinion of course.