由于debian11正式发布了，然后就想着直接升级了把，反正个人服务器，不求稳定，有问题自己随时修复，也算一个学习吧。

更新

先把系统更新到最新的

apt update

然后准备修改 /etc/apt/sources.list

修改sources.list

把所有的buster 修改为 bullseye
把buster/update 修改为 bullseye-security

注意 debian-security 这个 官网表示在debian11 时 会将版本号/update 修改为 版本号-security

下面是参考示例

## Note, this file is written by cloud-init on first boot of an instance
## modifications made here will not survive a re-bundle.
## if you wish to make changes you can:
## a.) add 'apt_preserve_sources_list: true' to /etc/cloud/cloud.cfg
##     or do the same in user-data
## b.) add sources in /etc/apt/sources.list.d
## c.) make changes to template file /etc/cloud/templates/sources.list.debian.tmpl
###

# See http://www.debian.org/releases/stable/i386/release-notes/ch-upgrading.html
# for how to upgrade to newer versions of the distribution.
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye-updates main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye-proposed-updates main non-free contrib
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye-backports main non-free contrib
## Major bug fix updates produced after the final release of the
## distribution.
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye-updates main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye-proposed-updates main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye-backports main contrib non-free

deb http://mirrors.cloud.aliyuncs.com/debian-security/ bullseye-security main non-free contrib
deb-src http://mirrors.cloud.aliyuncs.com/debian-security/ bullseye-security main non-free contrib

升级系统

apt update && apt full-upgrade

后面如果有提示可以直接回车

一般都是问是否使用包的配置文件，因为修改过，这时候尽量直接回车就好，保留现在的。