What you should realize in the to update/not to update "debate" is that they are two equally valid approaches to operating your Mavic. One way is not intrinsically "better" than another - just different. Like many other decisions in life, there are pro and con reasons for deciding whether or not to update your firmware, and the choice is
yours, not someone else's. What works for me may not work for you. What you like, I may not. What no one ever does is lay out the pros and cons for each path and with that information, let the user decide for themselves - instead of arguing that "my way is the best way". Recognizing that either route has its strengths and weaknesses at least arms the operator with complete knowledge, with which to make the best
personal decision.
A while back, in another post, I attempted to outline the pluses and minuses of each option. Very little has changed since then. I'll include it here, with updated FW numbers, but the underlying information hasn't changed dramatically. Turn left at the fork in the road or turn right. The choice is yours. But at least you'll know what's down the road on either route:
Reasons to go up to most current FW (4.300): You want the new DJI Go app Quickshot modes (Dronie, etc) and Panorama capabilities; You need Dynamic Home Point for your Active Track mode; You need to feel "current"; You don't mind new potential bugs/problems introduced by firmware changes. You need/want compatibility with newer 3rd party apps (Like Hangar 360, Autopilot, etc). You don't mind needing to pass a drone use test put out by DJI. You don't mind being forced to sign in to a DJI account or update your firmware (or wait for that update to complete) in order to use your Mavic - sometimes at the most inopportune time.
Reasons to move to 3.700: You need support for the
DJI Goggles; You want to use Fixed-Wing mode; You want to use Dual Remote Controller; You want to be able to turn off the remote controller low battery level warning; You don't want to have to remain logged in to your DJI account in order to fly.
Reasons to stay at/rollback to 3.400: Your Mavic works perfectly fine and you don't need/want the newest app functions; You don't want to be restricted by NFZs, You want to change your Mavic's flight parameters at will; You don't like DJI controlling the abilities of your Mavic.
Reasons to rollback to 3.700 with added mixed modules: You want the new DJI Go app Quickshot modes (Dronie, etc) and Panorama capabilities; You need/want compatibility with newer 3rd party apps. You don't want to be restricted by NFZs. You want to change your Mavic's flight parameters at will; You don't like DJI controlling the abilities of your Mavic. This is the best of both worlds (like going left
and right down the road) - but with the caveat that it takes a bit of knowledge on how to rollback your FW and how to mess with FW modules. If you don't want the added effort of learning a new skill, then either update or don't and don't worry about messing with the FW modules. Like "jailbreaking" your phone, it's not difficult but it's also not for the casual user.
Finally, the features of .400 are included in the features of .700 (no NFZ restrictions, ability to change your flight parameters), but with the added features of .700 on top of them Personally, I like the new Quickshot modes so I have all my Mavics on .700 with mixed modules ( and .700 instead of .400 - to use with the
Goggles).
The app is not the big difference. It's the firmware. Even with an updated app, you don't have the new features without the firmware update. Even with the new app, you don't have the restrictions of the newest firmware, though you get warnings. There's been no real beneficial upgrades to the newer app versions (without the concurrent firmware upgrades), though there have been a number of decent tweaks.