It looks like the brand new AVIC-W8400NEX is now available for sale on Crutchfield and other sites.
I'm really excited for the wireless Apple Carplay (and Android Auto if I ever switch). It looks like it also supports WiFi Miracast if you have an older Android phone or other device that supports it.
Hopefully you can use the controls while the car is driving or a bypass is discovered! 
EDIT: It looks like you can't play video from SD/USB to the rear displays when CarPlay is being used?!!
I've confirmed that you cannot play any external media (except DVD it seems) to the rear displays when carplay or android auto is being used. This seems to really limit the dual-zone capability of the unit making it somewhat pointless.
Overall the W8400NEX is a bit more snappy than the 8000NEX and the screen is a little nicer but I'm not sure it's worth the upgrade...
(FYI, the Kenwood stereos also don't allow rear video playback when carplay/android auto is being used... seems very strange!)
I just upgraded to the W8400NEX from the 8000NEX.
The screen is definitely a notable improvement. Better colors, brightness, and contrast.
It is significantly faster and more responsive.
Wireless Carplay works seemlessly. I kept having random dropouts with the 8000NEX.
Overall, I’m pleased with the upgrade.
One thing I miss (or can’t find!) is the old parking assist guide lines. It was a pain in the butt to setup, but it made parking much easier. It seems this is the first model to do away with them. To clarify, I am not talking about the sensor-based parking assist feature over the iDataLink Maestro connection... just the old-fashioned static lines you could set as an overlay on the backup camera.
I don’t see them in the manual, but figured I’d ask here if anyone has found them. I’ll be expressing my displeasure regarding their removal with Pioneer.
Did Pioneer get rid of the skip track buttons?
It appears to me they replaced it with a Siri button and back button instead.
Cant say for sure my local car stereo shops don’t have it in yet.
Good point! The physical track buttons on the radio are gone. I hadn’t noticed because I use the buttons on the steering wheel.
If you press the button to the right of the “home” button, a black quick control menu bar fills the lower third of the display, and includes software buttons for next/previous track, play/pause, settings, and the day/night dimmer.
Does it still have the absurd warning window every time you start the car that you have to touch to accept?
2 hours ago, axman said:Does it still have the absurd warning window every time you start the car that you have to touch to accept?
There is a warning which you can touch to acknowledge, but it goes away on its own after a few seconds.
Also, there is no longer a CarPlay warning window.
For those of you that have this unit, are you pleased with it? I've been using a z150BH in an 09 suburban but have since removed it from the vehicle since i recently traded it for a 2013 escalade. I was looking at the 8200nex but then was told about the w8400 that just came out.
8 hours ago, DJ Jamie said:For those of you that have this unit, are you pleased with it? I've been using a z150BH in an 09 suburban but have since removed it from the vehicle since i recently traded it for a 2013 escalade. I was looking at the 8200nex but then was told about the w8400 that just came out.
I had the 8000nex before upgrading to the W8400NEX.
Unless price is a big concern, I would go with the W8400NEX.
The W8400NEX feels like a true version 2.0 of the NEX platform. The NEX GUI has been updated for the first time. It is far less buggy and more responsive.
The 8000NEX, 8100NEX, 8200NEX, and 8201NEX were all essentially the same software and hardware, with only minor upgrades.
On 6/11/2018 at 2:40 AM, mapotter99 said:Good point! The physical track buttons on the radio are gone. I hadn’t noticed because I use the buttons on the steering wheel.
If you press the button to the right of the “home” button, a black quick control menu bar fills the lower third of the display, and includes software buttons for next/previous track, play/pause, settings, and the day/night dimmer.
Great tip, I don’t have steering wheel controls 
I found out these “ON screen skip buttons” don’t do anything in Apple carplay music source with google play music running. Anyone else try with stopify etc?
I upgraded from Avic Z140 to the AVH-W4400NEX last week. I never used the GPS on the Z140 and found it was very inaccurate hence I went to the 4400.
Compared to the Z140 this is MUCH MUCH faster and more responsive. Much better screen. and the Bluetooth works. I love the Android Auto (wired, since Samsung still does not support wireless).
Few concerns:
1- Missing parking line in back up camera view
2- Steering wheel phone off hook and hang up buttons do not work, while Android auto is running.
3- I used the MicroBypass, but the GPS still picks up the cars speed and locks up the menus when in motion. It re-enables them as soon as the speed is 0.
Anyone has any solutions for these?
2 hours ago, toyotaman said:I upgraded from Avic Z140 to the AVH-W4400NEX last week. I never used the GPS on the Z140 and found it was very inaccurate hence I went to the 4400.
Compared to the Z140 this is MUCH MUCH faster and more responsive. Much better screen. and the Bluetooth works. I love the Android Auto (wired, since Samsung still does not support wireless).
Few concerns:
1- Missing parking line in back up camera view
2- Steering wheel phone off hook and hang up buttons do not work, while Android auto is running.
3- I used the MicroBypass, but the GPS still picks up the cars speed and locks up the menus when in motion. It re-enables them as soon as the speed is 0.
Anyone has any solutions for these?
1- Call Pioneer and request this feature be added back. I’m wondering if someone backed into something after setting it up improperly and then sued Pioneer.
2- CarPlay works fine for me. Sorry, I can’t check Android Auto.
3- Have you done the software bypass? I’ll double check, but I haven’t noticed this.
No, i could not do the software bypass by holding my finger 1"from lower left corner of the screen in source off mode.
Nothing happens when i do that. Am i missing something?
1 hour ago, toyotaman said:No, i could not do the software bypass by holding my finger 1"from lower left corner of the screen in source off mode.
Nothing happens when i do that. Am i missing something?
It worked fine for me and allows access to the Nav settings while driving.
mpotter99, do you have the W4400 unit?
On 7/13/2018 at 6:46 AM, toyotaman said:mpotter99, do you have the W4400 unit?
No, I have the W8400.
Are you still able to use the software bypass for in motion video with the
AVIC-W8400NEX?
I'm wanting to purchase the
AVIC-W8400NEX
but I need to make sure the screen mirroring for android still works while in motion because I'm wanting to mirror android auto since my phone currently does not support the android auto wireless connect feature
On 8/17/2018 at 3:39 AM, CARL84 said:Are you still able to use the software bypass for in motion video with the
AVIC-W8400NEX?
Yes, the software bypass works the same as it always has on the W8400NEX.
I looked through the Owner's Manual and would like to understand if the [Mirror] Rear Display option also mirrors Android Auto?
Reason I am asking is because my factory head unit location is low in the dash and I have a factory navigation that is outdated. I would like to replace the factory GPS screen with a headrest monitor, if possible.
Just got the avic w8400nex installed today. And I cannot figure out how to mirror the head unit to the rear display.. I'm playing a video through a us thumb drive and it plays fine on the head unit. When I select the rear/mirror option nothing happens it's just a black screen. The video format is in mp4. Any suggestions?