一、保存备份

Ubuntu 24.04 之前，源配置文件路径为 /etc/apt/sources.list，而在此之后，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 ，使用下面命令进行备份原文件。

# 旧版本
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
# 新版本
sudo cp /etc/apt/sources.list.d/ubuntu.sources /etc/apt/sources.list.d/ubuntu.sources.bak

二、编辑换源

旧版本（2024.04之前）

清华源

# 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/ noble main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ 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://security.ubuntu.com/ubuntu/ noble-security main restricted universe multiverse
# deb-src http://security.ubuntu.com/ubuntu/ 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/ noble-proposed main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-proposed main restricted universe multiverse

阿里源

deb https://mirrors.aliyun.com/ubuntu/ noble main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ noble main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu/ noble-security main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ noble-security main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu/ noble-updates main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ noble-updates main restricted universe multiverse

# deb https://mirrors.aliyun.com/ubuntu/ noble-proposed main restricted universe multiverse
# deb-src https://mirrors.aliyun.com/ubuntu/ noble-proposed main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu/ noble-backports main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ noble-backports main restricted universe multiverse

中科大源

# 默认注释了源码仓库，如有需要可自行取消注释
deb https://mirrors.ustc.edu.cn/ubuntu/ noble main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ noble-security main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-security main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-updates main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-backports main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.ustc.edu.cn/ubuntu/ noble-proposed main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-proposed main restricted universe multiverse

新版本（2024.04之后）

清华源

Types: deb
URIs: https://mirrors.tuna.tsinghua.edu.cn/ubuntu/
Suites: noble noble-updates noble-backports
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

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

新版本之后的镜像源得用DEB822格式，不然会出现以下错误

复制并保存配置文件。

三、更新源

输入以下命令，更新一下本地软件包即可。

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get upgrade