Yi outdoor cameras different up to date firmware

I have 4 Yi Outdoor cameras. 3 have firmware 3.x and the 4th has firmware 9.x with newer features. All cameras show up to date firmware. Why cant the first 3 cameras be updated to the latest firmware to take advantage of the new detection features?

Hello! Great question, thanks for coming to the forum for more information. Are they all wired outdoor cameras or are any of them battery powered?

Did you purchase these at different times? or all at the same time?

They are all wired. The last one with 9.x was purchased about a yr after the first 3. Did you change the hardware. I notice the one with the 9.x is alerting on people way more than the 3.x ones…

They are all set to high sensitivity. How can i update the ones on 3.x to a newer firmware?