Bluetooth has evolved constantly over time and although all versions of the technology use the same 2.4GHz radio frequency (and are therefore all susceptible to the Bluetooth+USB3 problem
) the signal strength and intelligence of the error correction has advanced considerably to try and improve device performance and reliability.
It is important to understand that Bluetooth has always been backwards compatible. So if your laptop internally supports the latest Bluetooth 4.1 standard it should
function with an old Bluetooth mouse supporting v1 of the technology or a new one supporting v4. It's advisable though to have all your hardware (the support inside the laptop and the devices connecting to it) to all be on as similar version of the Bluetooth standard as possible, and at the same time as new a version of the standard as possible so that all the devices can benefit from the recent innovations made in the technology.