From what I understand the v3 will still be supported after the v4 release. There will be special commands for the new board I guess.

Yes for the 2nd board use your V3 and choose the V3 under board type dropdown box. Ofcourse the v4 board will have cool feature you want to make priority like the new camera integration :)

So updating to the latest ARC when I get the new V4 will not create any problems with my current project?

Nope. All previous revisions of the EZ-B are to remain supported by the software. Obviously anything before the V4 will be unable to use the V4s features but it shouldn't make any difference to current projects (depending on which version you currently run, if it's old there may be some issues since some stuff has changed but those updates are months old).

If I'm using a v3 and v4 simultaneously, can the v3 slave off the wifi on the v4 or do I need to get a uart wifi for the v3?

@doombot , the EZB firmware only allows connection direct to ARC. You will need to either connect the v3 with Bluetooth to your ARC hosting pc or you can buy a separate UART WiFi module and manually set it up to connect over your WiFi network. The seperate board still needs it's own independent connection from the other board to "talk" to ARC.

I'm sure I read somewhere that the V4 can be chained together, which may mean the V3 could be chained to a V4 depending on how it works... The I2C port on the V3 and V4 does open up the possibility that one may be able to control the other but I guess that side of things is currently only known to EZ-Robot staff.

Thanks guys for responding and answering my question. I have to choose one of ya. All gave good answers. Random drawing goes to..... Josh.....

I think we need a way to give credit to multiple people.

lol right, its not a contest anyways :)