升级ubuntu到22.04之后，更新源遇到了04Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details” 这个警告,解决方案如下：
首先查看key list,找到警告相关源的key
$ apt-key list Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)). /etc/apt/trusted.gpg -------------------- pub rsa2048 2016-09-25 [SC] [expired: 2021-04-18] 1B07 204C D71B 690D 409F 57D2 4ABE 1AC7 557B EFF9 uid [ expired] isv:ownCloud OBS Project <isv:ownCloud@build.opensuse.org> pub rsa2048 2015-10-28 [SC] BC52 8686 B50D 79E3 39D3 721C EB3E 94AD BE12 29CF uid [ unknown] Microsoft (Release signing) <gpgsecurity@microsoft.com> pub rsa4096 2017-04-05 [SC] DBA3 6B51 81D0 C816 F630 E889 D980 A174 57F6 FB06 uid [ unknown] Open Whisper Systems <support@whispersystems.org> sub rsa4096 2017-04-05 [E] /etc/apt/trusted.gpg.d/ubuntu-keyring-2012-cdimage.gpg ------------------------------------------------------ pub rsa4096 2012-05-11 [SC] 8439 38DF 228D 22F7 B374 2BC0 D94A A3F0 EFE2 1092 uid [ unknown] Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com> /etc/apt/trusted.gpg.d/ubuntu-keyring-2018-archive.gpg ------------------------------------------------------ pub rsa4096 2018-09-17 [SC] F6EC B376 2474 EDA9 D21B 7022 8719 20D1 991B C93C uid [ unknown] Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>导出相应key到单独的文件，假设有警告key是55AFCFAE (注:只需对应后8位即可)
$ apt-key export BE1229CF|sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/microsoft.gpg修改有问题源的配置文件，关联key文件位置. 源配置文件/etc/apt/sources.list.d目录下
deb [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/microsoft.gpg] https://packages.microsoft.com/repos/ms-teams stable main至此key到处都是单独的文件，与源配置文件关联成功，可以删除trusted.gpg中的key了.
另外，如果你在列表中找到一些，如果你在列表中找到一些key的状态是 [expired] 也可以用以下命令删除
$ sudo apt-key del 557BEFF9