I should follow up. As jesse mentioned, we are working on a fix right now that will support up to 11 devices.
Currently, if the USB Hub has the wifi dongle plugged in (which is required), it can support up to 5 devices smart devices max. Yogibears, Team Flags, Battery Buzzers, RFID readers, limit switches, etc are all smart devices.
Any smart devices that don't have the green sticker will detrimentally impact how many devices can be supported - maximum of three or four, depending on where they are plugged into the USB hub. As long as all of your smart devices have green stickers, you can ignore that complexity.
If you're looking for a quick way to get the 5th yogibear running, it turns out that you don't have to plug in the Battery Buzzer. The Battery Buzzer draws power directly from the PDB. If you unplug it, you won't see your battery voltage on dawn, but nothing else negative will happen.