1. 确保安装 update-manager-core这个包 如果没有安装执行以下命令

sudo apt install  update-manager-core

2.确保/etc/update-manager/release-upgrades这个文件的Prompt被设置为normar
此文件有三个可选项，nerver标识永不更新，normal表示正式版、lts表示只选择长期支持版本

# Default behavior for the release upgrader.

[DEFAULT]
# Default prompting behavior,valid options:
#
#  never  - Never check for a new release.
#  normal - Check to see if a new release is available.  If more than one new
#           release is found,the release upgrader will attempt to upgrade to
#           the release that immediately succeeds the currently-running
#           release.
#  lts    - Check to see if a new LTS release is available.  The upgrader
#           will attempt to upgrade to the first LTS release available after
#           the currently-running one.  Note that this option should not be
#           used if the currently-running release is not itself an LTS
#           release,since in that case the upgrader won't be able to
#           determine if a newer release is available.
Prompt=normal

3.执行

sudo do-release-upgrade

ok,跟着命令走就好了