how do you install note 8 software on a note 3?

Solution
The software, meaning the OS (operating system) which is Android is on both devices. The difference is the 'version' of the OS. Installing another OS that is not offered on the device as an update requires the device be rooted and that in itself is not a good move. It can easily brick a device. Also, a device that is still using a much older OS may not be able to handle the newer version as it will take up way more space on the device and use more resources which the phone may not be able to handle. The Note 3 came out 5 years ago and it is likely it could not handle the newer OS and newer apps.
The software, meaning the OS (operating system) which is Android is on both devices. The difference is the 'version' of the OS. Installing another OS that is not offered on the device as an update requires the device be rooted and that in itself is not a good move. It can easily brick a device. Also, a device that is still using a much older OS may not be able to handle the newer version as it will take up way more space on the device and use more resources which the phone may not be able to handle. The Note 3 came out 5 years ago and it is likely it could not handle the newer OS and newer apps.
 
Solution