Help fneeded to fix error on Skype key problem so update to 21.3 can be done

I have linux mint Victoria 21.2.

Wanting to update to 21.3. I found a utube describing how to update. It described how to use Timeshift to get a backup. I am up to date on update manager. He suggested I refresh that screen. It resulted in

An error occurred:
W: https://repo.skype.com/deb/dists/stable/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

Is it important that I get this resolved before I update to version 21.3 ?
If so, how do I fix this ? I will need the commands required to fix this.
Or is this something I can ignore ?

Now update manager is in stuck mode checking for package updates....

Used terminal to check updates:

libre@libre-Latitude-3540:~$ sudo apt update
[sudo] password for libre:
Ign:1 http://packages.linuxmint.com victoria InRelease
Hit:2 http://babylon.cs.uh.edu/mirror-sites/ubuntu jammy InRelease
Hit:3 http://packages.linuxmint.com victoria Release
Hit:4 http://babylon.cs.uh.edu/mirror-sites/ubuntu jammy-updates InRelease
Hit:5 http://babylon.cs.uh.edu/mirror-sites/ubuntu jammy-backports InRelease
Hit:6 https://linux.teamviewer.com/deb stable InRelease
Hit:7 http://security.ubuntu.com/ubuntu jammy-security InRelease
Hit:9 https://repo.skype.com/deb stable InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
W: https://repo.skype.com/deb/dists/stable/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
libre@libre-Latitude-3540:~$

After posting this, I will restart and see if that fixes update manager that is stuck.
To restart, it said mint update Refreshing available updates. I restarted anyway.
No longer stuck on update manager. Not sure why it got stuck...

Thanks in advance for help on this.