I don't understand why I can't update/grade from 20.10 to 21.04

I am wanting to update from Ubuntu 20.10 to 21.04.

When I first tried I was getting an error:

W: GPG error: http://ddebs.ubuntu.com groovy Release: The following signatures were invalid: EXPKEYSIG C8CAB6595FDFF622 Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <[email protected]>
E: The repository 'http://ddebs.ubuntu.com groovy 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.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://ddebs.ubuntu.com groovy-updates Release: The following signatures were invalid: EXPKEYSIG C8CAB6595FDFF622 Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <[email protected]>
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://ddebs.ubuntu.com groovy-proposed Release: The following signatures were invalid: EXPKEYSIG C8CAB6595FDFF622 Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <[email protected]>

Which seems that the key has expired. (Shrug)

I fixed it by doing this:

sudo apt install --reinstall ubuntu-dbgsym-keyring

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F2EDC64DC5AEE1F6B9C621F0C8CAB6595FDFF622

sudo apt-get update

But it only got rid of that part.

When I try to sudo dist-upgrade this happens:

 sudo apt dist-upgrade 
[sudo] password for me: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  dh-python
0 to upgrade, 0 to newly install, 0 to remove and 1 not to upgrade.

So I don't understand why it isn't updating to 21.04

Please, someone. Thanks in advance.

Solution 1:

You're not using the correct command.

The command you should run is sudo do-release-upgrade .

apt dist-upgrade is something entirely different.

See: What is "dist-upgrade" and why does it upgrade more than "upgrade"?