无法升级18.04至20.04/20.10，因为保存了软件包

Question

我正试着从18.04升级到20.10。我的理解是，我首先需要更新到20.04，然后更新到20.10。我正在遵循此页上的说明。

当我运行sudo apt upgrade时，我会收到这样的消息：

The following packages have been kept back:   
  frei0r-plugins libssh-4 
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.

我不知道为什么这些东西会被阻止。我隐约记得安装了第一个软件包，但不知道我安装了什么，需要第二个软件包。

当我运行sudo apt dist-upgrade时，我会得到相同的消息。

然后，当我转到sudo apt do-release-upgrade时，我会得到以下错误：

Checking for a new Ubuntu release
Please install all available updates for your release before upgrading.

好吧，我想这和保留的包裹有关吧？我读到了一个地方，我可以把它们拆掉，但这不管用：

$ sudo apt-mark unhold frei0r-plugins libssh-4
frei0r-plugins was already not hold.
libssh-4 was already not hold.

在另一个地方，我读到sudo aptitude safe-upgrade可能会解决这个问题。它安装了几个i386包，但之后我仍然得到了与以前相同的消息/错误，当我试图升级时。

我还读到我应该运行apt list --upgradable，并且sudo apt-get install每个包都单独列出。但是当我尝试得到这个错误时：

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 frei0r-plugins : Depends: libopencv-objdetect4.2 but it is not going to be installed
                  Depends: libopencv-video4.2 but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

另外，当我试图安装第二个依赖项时，我说它将删除四个还押包，因为我经常使用这个程序，所以我不想要这些包！

Answer 1

您能否尝试卸载frei0r插件和libssh-4，然后尝试升级。如果成功，那么重新安装frei0r-plugins和libssh-4。您需要这两个安装吗？https://packages.debian.org/sid/libssh-4 https://frei0r.dyne.org/

Answer 2

当我试图更新时，我也遇到了同样的问题

我解决了这一问题，迫使包更新如下：

sudo apt-get install {package-name}

注意：

不确定这是否是正确的方法，但它对我有效:)