16.04要用22.04 apt source碰到key的問題

The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93C
NO_PUBKEY 871920D1991BC93C

$ sudo apt-get update
Hit:1 http://tw.archive.ubuntu.com/ubuntu bionic InRelease
Hit:2 http://tw.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:3 http://tw.archive.ubuntu.com/ubuntu bionic-backports InRelease
Get:4 http://mirrors.163.com/ubuntu jammy InRelease [270 kB]
Hit:5 http://security.ubuntu.com/ubuntu bionic-security InRelease
Err:4 http://mirrors.163.com/ubuntu jammy InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 871920D1991BC93C
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Didn't work

$ sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 871920D1991BC93C
Executing: /tmp/apt-key-gpghome.SPEq7suR5V/gpg.1.sh --keyserver keys.gnupg.net --recv-keys 871920D1991BC93C
gpg: keyserver receive failed: No name

It works.

$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv 871920D1991BC93C
[sudo] password for ubuntu:
Executing: /tmp/apt-key-gpghome.1L20qFwiJG/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com --recv 871920D1991BC93C
gpg: key 871920D1991BC93C: 4 signatures not checked due to missing keys
gpg: key 871920D1991BC93C: public key "Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>" imported
gpg: Total number processed: 1
gpg:               imported: 1