Bluetooth 4.2 was released in late 2014. It was probably built into computers starting sometime in 2015 or later.
You might check with Lenovo to see if there is a firmware/software updated for the Bluetooth device in your laptop. (Apple provided a software update for my older iPhone 6 that updated the Bluetooth from 4.0 to 4.2 without a hardware change but I don’t know if that is possible with the Lenovo hardware/software in your laptop). Lenovo has a System Update utility that we use at work to find and install relevant updates (software and BIOS) for some Lenovo W series laptops we use.
You might also be able to replace the Bluetooth hardware in the laptop with a newer version that is 4.2 or later. Some Windows notebooks have the radios on small replaceable cards but that again depends on the model. Some BIOS implementations allow for changing the radios but others prevent it - in the old days before Lenovo purchased the IBM ThinkPad line/name, that was true for some I used.
Another possibility would be to use a USB connected Bluetooth adapter (you might have to disable the built-in one). Oticon provided a Sennheisser BTD 800 USB dongle with my ConnectClip for connecting to computers with problematic Bluetooth implementations. I use it with my fairly new desktop iMac Pro at home - it works well where the built-in bluetooth 5.0 does not. The Bluetooth 5.0 in my work MacBook Pro works fine without the BTD 800. Go figure …