is it safe at this point to update both of these? I haven't seen much discussion lately so I'm hoping that's a good sign.

There's been quite a few that have updated everything, including me, and after some have done extensive testing all the systems, all systems work as advertised.

Here is a procedure that has worked for me...

There has to be some subtle difference as to how some did their upgrades vs. how others did it..I am pretty picky when it comes to deleting and reinstalling software but it seems to work for me.
Procedure for me was:
Turn on computer I use for my updates (a 7 year old laptop/PC that just barely runs Windows 7 and does nothing but iTunes and the Phantom Softwares and not a single other program or app or anti virus software is on it).
(If you are a new Phantom owner and have no software loaded, skip this step!) Completely Uninstall old 3.6 Phantom Vision Assistant and RC Assistant software from the computer using the windows uninstaller and delete shortcuts from the desktop.
Restart computer/Flush the Toilet (basically make sure everything I had deleted went where it was supposed to go and no left over cache or crap info was floating around and to make sure no system files were accidentally deleted and no errors on the restart).
Download new software .exe files for Phantom Vision Assistant, RC Assistant and for new users you will also need the DJI Win Driver Installer.

Install new softwares

Restart computer/Flush the Toilet (basically make sure everything I installed went where it was supposed to go and no left over cache or crap info info was floating around and that I had no errors on the restart).
Plug Phantom into computer
Turn on RC and TX
Take Props off of Phantom! and Turn on Phantom and let it warm up (no motors running!, just turn on the battery)..
NOTE: I always turn on the RC then TX and then the Phantom in the same order after I plug into the computer as if I were going to fly it.
Launch 3.8 Phantom Vision Assistant software
Update Software and verify updates were installed.
Check all settings on Phantom (IMU etc. and made sure none of my NAZA-M or anything defaulted back to Phantom, IOC was still on and so on),
Check RC Calibration
Close the program
Turn off Phantom then Tx Then RC
unplug Phantom from computer
Plug in RC, then turn on RC then TX then Phantom
Launch RC Vision Assistant
Check for updates, apply updates if any updates present,
Recheck RC calibration and settings
Close RC Assistant
Turn off Phantom then TX then RC
Unplug RC from computer
Turn off computer
Install Props
Go outside
Go through Preflight
Turn on RC then TX then Phantom and do the compass dance once SATS acquired.
fly the Phantom with a few basic maneuvers then fly it like You stole it...
Fortunately for me the update has been flawless.

Hey, do you guys have the RE700 Extender? If so, did you do the extender update in the Vision App? It says it enables cellular data use but I'm not sure if it does any other update. I thought I read somewhere that people weren't doing this update for some reason. With all the reading I've been doing, I just can't remember.

Jerry

no problem upgrading. I did experience something strange though, a popup in the app saying the compass needed to be recalibrated. This happened before and after updating everything. I was getting error 27 in the desktop app indicating a problem with the GPS calibration? Everything seems fine now.