Tvheadend

I am running Tvheadend version 4.2.8-36~g5bdcfd8ac on Ubuntu server 20.04.3 LTS, and have just become aware of some fixes that were made about a year ago that are in the current "unstable" version, that may well solve some problems I am having with audio and video being out of sync on some streaming (IPTV) sources. I've always installed Tvheadend versions using the instructions on the page at https://tvheadend.org/projects/tvheadend/wiki/AptRepositories and therefore, in my /etc/apt/sources.list.d directory there is a file called sources.list.d that contains this single line:

deb https://apt.tvheadend.org/stable focal main

So my question is, if I edited that like to change "stable" to "unstable", and then did "sudo apt update && sudo apt upgrade", would that be sufficient to upgrade my system to the latest unstable version, and is doing that likely to cause any problems or cause any of my existing settings to be lost? Is the "unstable" version still stable enough that you suggest using it in a case like this?

And also, if for some reason the upgrade does cause problems, can I easily roll back to the current stable version? I realize I should probably back up my /home/hts directory, but would there be anything else I would need to back up if I wanted to make sure I could go back to the stable version, just in case there is a problem?