Recently, we received the feedback that after installing a third-party package manually, the system update failed. After testing, we found that in most cases, the reason is not the installed third-party package, but the package that the third-party package depends on. During deepin upgrade, the dependencies versions will be seriously conflicted with the package versions in system upgrade.
When the user upgrades deepin, according to the priority policy, the low version packages will be uninstalled, which will result in system failure that user cannot enter the desktop. Although we have performed multiple rounds of testing before the release, as we only test system upgrade in standard repositories without user scenarios such as third-party packages installed, we cannot perform simulations and thus unable to perform coverage tests.


In order to avoid similar problems to a certain extent, we have adjusted the priority of the package repository. If the package version is inconsistent with the official repository and the package is not set with apt-mark command (sudo apt-mark hold package), it will be synchronized to the official version when updating, ensuring stable system for common users. If you are sure that you need it and have the ability to resolve the dependencies, please use apt-mark to force keep your higher version after package installation. To get the new versions of software such as code and chrome, you can ask for official updates.

Here is the example to prevent application downgrade:
To keep your version of google chrome, please use apt-mark command:

sudo apt-mark hold google-chrome-stable


Source post: https://bbs.deepin.org/post/168478

In V15.8,we'll cancel this policy.