During do-release-upgrade -d I received the following error:
Reading package lists...
Building dependency tree...
Reading state information...
Correcting dependencies... failed.
The following packages have unmet dependencies:
aptitude : Depends: libsigc++-2.0-0c2a (>= 2.0.2) but it is not installable
compiz-core : Depends: libglibmm-2.4-1c2a (>= 2.36.2) but it is not installable
Depends: libsigc++-2.0-0c2a (>= 2.0.2) but it is not installable
gvfs-fuse : Depends: gvfs (= 1.28.2-1ubuntu1~16.04.3) but 1.20.3-0ubuntu1.2 is installed
hplip : Depends: libhpmud0 (= 3.14.3-0ubuntu3.4) but 3.16.3+repack0-1 is installed
Depends: libsane-hpaio (= 3.14.3-0ubuntu3.4) but 3.16.3+repack0-1 is installed
Depends: hplip-data (= 3.14.3-0ubuntu3.4) but 3.16.3+repack0-1 is installed
Depends: printer-driver-hpcups (= 3.14.3-0ubuntu3.4) but 3.16.3+repack0-1 is installed
libalgorithm-diff-xs-perl : Depends: perlapi-5.18.1 but it is not installable
libapparmor-perl : Depends: perlapi-5.18.2 but it is not installable
libapt-pkg-perl : Depends: perlapi-5.18.1 but it is not installable
libc6-dbg : Depends: libc6 (= 2.19-0ubuntu6.15) but 2.23-0ubuntu11.2 is installed
libcairo-perl : Depends: perlapi-5.18.1 but it is not installable
libclone-perl : Depends: perlapi-5.18.1 but it is not installable
libcwidget3 : Depends: libsigc++-2.0-0c2a (>= 2.0.2) but it is not installable
libdbd-mysql-perl : Depends: perlapi-5.18.2 but it is not installable
libdbi-perl : Depends: perlapi-5.18.1 but it is not installable
libebackend-1.2-10 : Depends: libedataserver-1.2-21 (>= 3.17.90) but it is not installed
libfile-fcntllock-perl : Depends: perlapi-5.18.1 but it is not installable
libglib-perl : Depends: perlapi-5.18.1 but it is not installable
libglib2.0-bin : Depends: libglib2.0-0 (= 2.40.2-0ubuntu1.1) but 2.48.2-0ubuntu4.6 is installed
libgtk2-perl : Depends: perlapi-5.18.2 but it is not installable
libhtml-parser-perl : Depends: perlapi-5.18.1 but it is not installable
libio-pty-perl : Depends: perlapi-5.18.1 but it is not installable
liblist-moreutils-perl : Depends: perlapi-5.18.1 but it is not installable
liblocale-gettext-perl : PreDepends: perlapi-5.18.1 but it is not installable
libnet-dns-perl : Depends: perlapi-5.18.1 but it is not installable
libnet-libidn-perl : Depends: perlapi-5.18.1 but it is not installable
libnet-ssleay-perl : Depends: perlapi-5.18.2 but it is not installable
libnm-gtk0 : Depends: libnm-gtk-common (= 0.9.8.8-0ubuntu4.5) but 1.2.6-0ubuntu0.16.04.4 is installed
libnux-4.0-0 : Depends: libsigc++-2.0-0c2a (>= 2.0.2) but it is not installable
libonline-accounts-client1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libonline-accounts-daemon1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libonline-accounts-qt1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
liboxideqt-qmlplugin : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
liboxideqtcore0 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
liboxideqtquick0 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libpam-systemd : Depends: systemd-services (= 204-5ubuntu20.31)
libpango-perl : Depends: perlapi-5.18.1 but it is not installable
libperl5.18 : Depends: perl-base (= 5.18.2-2ubuntu1.7) but 5.22.1-9ubuntu0.9 is installed
libperlio-gzip-perl : Depends: perlapi-5.18.1 but it is not installable
libpurple0 : Depends: perlapi-5.18.2 but it is not installable
libqgsttools-p1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libqofono-qt5-0 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Recommends: ofono (>= 1.16) but it is not installed
libqt5gui5 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5multimedia5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5multimedia5-plugins : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libqt5multimediaquick-p5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libqt5multimediawidgets5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libqt5qml5 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5quick5 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5quicktest5 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5webkit5 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5widgets5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libqt5xmlpatterns5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libsocket6-perl : Depends: perlapi-5.18.2 but it is not installable
libstdc++-5-dev : Depends: libstdc++6 (>= 5.5.0-12ubuntu1~14.04) but 5.4.0-6ubuntu1~16.04.12 is installed
libstdc++-6-dev : Depends: libstdc++6 (>= 6.5.0-2ubuntu1~14.04.1) but 5.4.0-6ubuntu1~16.04.12 is installed
libstdc++-7-dev : Depends: libstdc++6 (>= 7.4.0-1ubuntu1~14.04~ppa1) but 5.4.0-6ubuntu1~16.04.12 is installed
libstdc++6 : Depends: gcc-5-base (= 5.4.0-6ubuntu1~16.04.12) but 5.5.0-12ubuntu1~14.04 is installed
libsub-identify-perl : Depends: perlapi-5.18.1 but it is not installable
libsub-name-perl : Depends: perlapi-5.18.1 but it is not installable
libterm-readkey-perl : Depends: perlapi-5.18.1 but it is not installable
libtext-charwidth-perl : Depends: perlapi-5.18.1 but it is not installable
libtext-iconv-perl : Depends: perlapi-5.18.1 but it is not installable
libtext-soundex-perl : Depends: perlapi-5.18.1 but it is not installable
libthumbnailer-qt1.0 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libubuntu-download-manager-client1 : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
libubuntu-download-manager-common1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libubuntugestures5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libubuntuoneauth-2.0-0 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libubuntutoolkit5 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
libudm-common1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
libuuid-perl : Depends: perlapi-5.18.1 but it is not installable
onboard : Depends: python3 (>= 3.5~) but 3.4.0-0ubuntu2 is installed
pay-ui : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
php5 : Depends: libapache2-mod-php5 (>= 5.5.9+dfsg-1ubuntu4.29) but it is not installable or
libapache2-mod-php5filter (>= 5.5.9+dfsg-1ubuntu4.29) but it is not installable or
php5-cgi (>= 5.5.9+dfsg-1ubuntu4.29) but it is not installable or
php5-fpm (>= 5.5.9+dfsg-1ubuntu4.29) but it is not installable
python3 : Depends: python3-minimal (= 3.4.0-0ubuntu2) but 3.5.1-3 is installed
Depends: libpython3-stdlib (= 3.4.0-0ubuntu2) but 3.5.1-3 is installed
python3-uno : Depends: python3 (>= 3.5~) but 3.4.0-0ubuntu2 is installed
python3-yaml : Depends: python3 (>= 3.5~) but 3.4.0-0ubuntu2 is installed
qml-module-qt-labs-folderlistmodel : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qt-labs-settings : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qtfeedback : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qtmultimedia : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qtquick-dialogs : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-qtquick-layouts : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-qtquick-localstorage : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qtquick-privatewidgets : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-qtquick-xmllistmodel : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-qttest : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-qtwebkit : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-components : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-ubuntu-layouts : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-onlineaccounts : Depends: libqt5core5a (>= 5.4.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-onlineaccounts-client : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-onlineaccounts2 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-performancemetrics : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-test : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
qml-module-ubuntu-thumbnailer0.1 : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-ui-extras-browser : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
qml-module-ubuntu-web : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
rhythmbox : Depends: rhythmbox-data (= 3.0.2-0ubuntu2) but 3.3-1ubuntu7 is installed
Depends: gir1.2-rb-3.0 (= 3.0.2-0ubuntu2) but 3.3-1ubuntu7 is installed
rhythmbox-mozilla : Depends: rhythmbox (= 3.3-1ubuntu7) but 3.0.2-0ubuntu2 is installed
rhythmbox-plugin-cdrecorder : Depends: rhythmbox (= 3.3-1ubuntu7) but 3.0.2-0ubuntu2 is installed
rhythmbox-plugin-magnatune : Depends: rhythmbox (= 3.3-1ubuntu7) but 3.0.2-0ubuntu2 is installed
rhythmbox-plugin-zeitgeist : Depends: rhythmbox (>= 3.3-1ubuntu7) but 3.0.2-0ubuntu2 is installed
rhythmbox-plugins : Depends: python3 (>= 3.5~) but 3.4.0-0ubuntu2 is installed
Depends: rhythmbox (= 3.3-1ubuntu7) but 3.0.2-0ubuntu2 is installed
signon-ui-x11 : Depends: libproxy1v5 (>= 0.4.11) but it is not installed
Depends: libqt5core5a (>= 5.4.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
thumbnailer-service : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
ubuntu-push-client : Depends: libqt5core5a (>= 5.4.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
unity : Depends: libsigc++-2.0-0c2a (>= 2.0.2) but it is not installable
Depends: libunity-core-6.0-9 (= 7.2.6+14.04.20160408-0ubuntu1) but 7.4.5+16.04.20190312-0ubuntu1 is installed
unity-plugin-scopes : Depends: libqt5core5a (>= 5.5.1) but 5.2.1+dfsg-1ubuntu14.3 is installed
unity-settings-daemon : Depends: gnome-settings-daemon-schemas (< 3.10) but 3.18.2-0ubuntu3.1 is installed
unity8-private : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
webapp-container : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
webbrowser-app : Depends: libqt5core5a (>= 5.5.0) but 5.2.1+dfsg-1ubuntu14.3 is installed
Depends: qtbase-abi-5-5-1
I have not be able to resolve the unmet dependencies and am afraid to reboot the server for it might not boot into OS with do-release-upgrade errors.
/etc/apt/sources.listlook like? Please [edit] your question to provide the contents. “am afraid to reboot the server for it might not boot into OS with do-release-upgrade errors.” These errors are pre-upgrade checks. If you quit right after getting them (I guess you got a prompt), you should be safe. However, doing a backup before upgrading the OS is always a good thing. – Melebius Nov 02 '20 at 14:18