全新安装的系统 16.04LTS，仅安装了 Xenial 包。
sudo apt install libgnutls-dev
结果是
Reading package lists... Done
Building dependency tree
Reading state information... Done
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:
libgnutls-dev : Depends: libgnutls30 (= 3.4.10-4ubuntu1) but 3.4.10-4ubuntu1.4 is to be installed
Depends: libgnutls-openssl27 (= 3.4.10-4ubuntu1) but 3.4.10-4ubuntu1.4 is to be installed
Depends: libgnutlsxx28 (= 3.4.10-4ubuntu1) but it is not going to be installed
Depends: nettle-dev but it is not going to be installed
Depends: libtasn1-6-dev but it is not going to be installed
Depends: libp11-kit-dev but it is not going to be installed
Depends: libidn11-dev (>= 1.31) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
错误消息（xxx 存在，但需要安装 xxxx+version）毫无意义。除了列出的软件包之外，没有其他需要安装的软件包。
sudo apt install -f结果一无所获：
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
apt-cache policy libgnutls-dev
给出
libgnutls-dev:
Installed: (none)
Candidate: 3.4.10-4ubuntu1
Version table:
3.4.10-4ubuntu1 500
500 http://au.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
有人有什么建议吗？
答案1
libgnutls-devxenial 上的当前版本是3.4.10-4ubuntu1.4。
看来您禁用了xenial-updates存储库。
在桌面上打开软件与更新（
software-properties-gtk）， 去更新标签并检查xenial-security和xenial-updates。在服务器上你应该有以下行
/etc/apt/sources.list：deb http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse
并尝试再次安装。