[timeAbove]

hello

i need help about some warning messages after i run

Code

apt-get update

i get this

apt-get update
Hit:1://repo.skype.com/deb stable InRelease                           
Ign:2 ://archive.canonical.com precise InRelease                       
Get:3 ://archive.canonical.com precise Release [8,180 B]
Get:4 ://archive.canonical.com precise Release.gpg [181 B] 
Ign:4 ://archive.canonical.com precise Release.gpg         
Get:5 ://kali.download/kali kali-rolling InRelease [30.6 kB]
Get:6 ://kali.download/kali kali-rolling/main amd64 Packages [18.3 MB]
Get:7 ://kali.download/kali kali-rolling/main amd64 Contents (deb) [42.7 MB]
Get:8 ://kali.download/kali kali-rolling/non-free amd64 Packages [221 kB]
Get:9 ://kali.download/kali kali-rolling/non-free amd64 Contents (deb) [897 kB]
Get:10 ://kali.download/kali kali-rolling/contrib amd64 Packages [110 kB]
Get:11 ://kali.download/kali kali-rolling/contrib amd64 Contents (deb) [160 kB]
Reading package lists... Done                                               
W: ://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.
W: ://archive.canonical.com/dists/precise/Release.gpg: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
W: GPG error: ://archive.canonical.com precise Release: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository '://archive.canonical.com precise Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

i'm not totally new but  i tried and read something but i dont  succeed in resolving this

please help

[DramaKing]

You probably need to remove the Skype and Canonical repos and replace them with updated ones. Might have to give up Skype.

[timeAbove]

About Skype repos i think i solve the problem but about Canonical repos i somehow dont see the message after update command because i delete as i read here https askubuntu.com/questions/1120194/e-the-repository-http-archive-canonical-com-precise-release-is-not-signed.

My question is, is it good and save because in the future may not be updated anymore with apt-get update/upgrade this canonical repos?
I'm asking this because after update command i saw more lines, now it is only 2 lines as usual lines.