情况：
我有几台运行现代硬件的机器，16.04主要用于科学计算。随着新 LTS 的出现，我希望将它们升级到20.04以稳定性和可靠性为关键组件。如果可能，我会保留unity桌面而不是切换 Gnome。
问题：采取的最佳方法是先升级18.04还是直接升级到20.04第一点发布？可以在不破坏统一性的情况下升级到新的 LTS 吗？
随着发布日期的临近，将保持此帖子更新。
我在更新 ubuntu 16.04 LTS 时收到此类消息：
W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by key 4CCA1EAF950CEE4AB83976DCA040830F7FAC5991 uses weak digest algorithm (SHA1)
W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by key 3B068FB4789ABE4AEFA3BB491397BC53640DB551 uses weak digest algorithm (SHA1)
谁能帮我？
我正在使用 reprepro 托管一些内部存储库。
将客户端升级到 Ubuntu 16.04 后，apt-get update会发出警告“InRelease: Signature by key ... uses weak digest algorithm (SHA1)”。
InRelease 文件像这样开始：
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
因此，reprepro 已使用 SHA1 对 InRelease 文件进行签名。如何将其更改为 SHA256 或 SHA512？
当我尝试更新我的Ubuntu 16.04时出现此错误。我已经尝试了一些解决方案，但到目前为止没有任何效果。
错误：
W: http://archive.canonical.com/ubuntu/dists/precise/Release.gpg: Signature by key 630239CC130E1A7FD81A27B140976EAF437D05B5 uses weak digest algorithm (SHA1)
W: http://us.archive.ubuntu.com/ubuntu/dists/precise-security/InRelease: Signature by key 630239CC130E1A7FD81A27B140976EAF437D05B5 uses weak digest algorithm (SHA1)
W: GPG error: http://extras.ubuntu.com/ubuntu precise Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192
W: The repository 'http://extras.ubuntu.com/ubuntu precise Release' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation …每当我单击软件更新程序时，它都会显示无法下载存储库信息。
这几天一直在说这个，我不知道为什么，我的互联网连接很好，我可以手动下载软件。
有时当我单击“确定”时它会崩溃，然后尝试再次查找更新并给我相同的消息。
有任何想法吗？
[编辑] 我刚刚尝试了一个答案，在那里我重置了下载的来源，但我收到了这条消息：
W:The repository 'http://ppa.launchpad.net/noobslab/noobslab-conky/ubuntu xenial Release' does not have a Release file.,
W:Data from such a repository can't be authenticated and is therefore potentially dangerous to use.,
W:See apt-secure(8) manpage for repository creation and user configuration details.,
W:https://content.runescape.com/downloads/ubuntu/dists/trusty/InRelease: Signature by key AAC9264309E4D717441DB9527373B12CE03BEB4B uses weak digest algorithm (SHA1),
E:Failed to fetch http://ppa.launchpad.net/noobslab/noobslab-conky/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found,
E:Some index files failed to download. They have been ignored, or old ones used instead.