升級到fedora 31

• 將現有的fedora 30更新

dnf upgrade --refresh

• 安裝系統升級插件

dnf install dnf-plugin-system-upgrade

• 升級到fedora 31

dnf system-upgrade download --releasever=31

• 等待下載完成後, 可能會報一個錯, 官方沒有說起.

警告：/var/lib/dnf/system-upgrade/fedora-39217cb7243e0d8e/packages/dnf-4.2.9-5.fc31.noarch.rpm: 頭V3 RSA/SHA256 Signature, 密鑰 ID 3c3359c4: NOKEY
Fedora 31 - x86_64 - aliyun                                                                                                                                                                                                                                       0.0  B/s |   0  B     00:00    
Curl error (37): Couldn't read a file:// file for file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64 [Couldn't open file /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64]
下載的軟件包保存在緩存中，直到下次成功執行事務。
您能夠經過執行 'dnf clean packages' 刪除軟件包緩存。
[root@dev5 ~]# rpmkeys --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64
錯誤：/etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64：導入讀取時失敗(2)。

• 運行下面的指令後, 再dnf system-upgrade download --releasever=31便可.

rpmkeys --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-31-x86_64

• 重啓系統.

dnf system-upgrade reboot