APT-GET update Invalid signatures

I had this issue when updating Kali linux vm for the first time.

root@kali:~# apt-get update
Get:1 http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease [30.5 kB]
Err:1 http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease
 The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository <devel@kali.org>
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease: The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository <devel@kali.org>
W: Failed to fetch http://http.kali.org/kali/dists/kali-rolling/InRelease The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository <devel@kali.org>
W: Some index files failed to download. They have been ignored, or old ones used instead.

This solution did not work and update ends with error as above:

rm -rf /var/lib/apt/lists
apt-get update 
apt-get install kali-archive-keyring

Working solution as below:

Add the gpg key:

gpg --keyserver hkp://keys.gnupg.net --recv-key 7D8D0BF6

Check the fingerprint:

gpg --fingerprint 7D8D0BF6

Sample output:

pub   rsa4096 2012-03-05 [SC] [expires: 2021-02-03]
      44C6 513A 8E4F B3D3 0875  F758 ED44 4FF0 7D8D 0BF6
uid           [ unknown] Kali Linux Repository <devel@kali.org>
sub   rsa4096 2012-03-05 [E] [expires: 2021-02-03]

then :

gpg -a --export 7D8D0BF6 | apt-key add -
apt update

Source: Stack Exchange