对于 Ubuntu 不再支持的版本，请参考 Ubuntu 旧版本帮助。

在 Ubuntu 24.04 之前，Ubuntu 的软件源配置文件使用传统的 One-Line-Style，路径为 /etc/apt/sources.list；从 Ubuntu 24.04 开始，Ubuntu 的软件源配置文件变更为 DEB822 格式，路径为 /etc/apt/sources.list.d/ubuntu.sources。

将系统自带的对应文件做个备份，然后根据格式的选择下面对应的内容替换，即可使用选择的软件源镜像。

传统格式（/etc/apt/sources.list）
Ubuntu 版本
Ubuntu 24.04 LTS (noble)
启用源码源
启用 proposed
强制安全更新使用镜像

默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-updates main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-updates main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-backports main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-backports main restricted universe multiverse

以下安全更新软件源包含了官方源与镜像站配置，如有需要可自行修改注释切换

deb http://ports.ubuntu.com/ubuntu-ports/ noble-security main restricted universe multiverse

deb-src http://ports.ubuntu.com/ubuntu-ports/ noble-security main restricted universe multiverse

预发布软件源，不建议启用

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-proposed main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ noble-proposed main restricted universe multiverse

DEB822 格式（/etc/apt/sources.list.d/ubuntu.sources）
Ubuntu 版本
Ubuntu 24.04 LTS (noble)
启用源码源
启用 proposed
强制安全更新使用镜像
Types: deb
URIs: https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports
Suites: noble noble-updates noble-backports
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释

Types: deb-src

URIs: https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports

Suites: noble noble-updates noble-backports

Components: main restricted universe multiverse

Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

以下安全更新软件源包含了官方源与镜像站配置，如有需要可自行修改注释切换

Types: deb
URIs: http://ports.ubuntu.com/ubuntu-ports/
Suites: noble-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Types: deb-src

URIs: http://ports.ubuntu.com/ubuntu-ports/

Suites: noble-security

Components: main restricted universe multiverse

Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

预发布软件源，不建议启用

Types: deb

URIs: https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports

Suites: noble-proposed

Components: main restricted universe multiverse

Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Types: deb-src

URIs: https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports

Suites: noble-proposed

Components: main restricted universe multiverse

Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

因镜像站同步有延迟，可能会导致生产环境系统不能及时检查、安装上最新的安全更新，不建议替换 security 源。