Upgrading mediasoup libraries to latest version

I am using mediasoup-client - 3.3.12 in the client side and mediasoup - 3.4.8 in the server side.

Is it possible to update the mediasoup libraries without editing much of existing code and use the new features of the latest mediasoup libraries?

I have upgraded the libraries to the latest version but I am unable to hear the audio. Could you please tell me how to fix it?

Should be just fine, major version is the same. Try upgrading one piece at a time and maybe not all the way to find out when and why exactly audio disappears.