$ ./Nextcloud-2.5.1-x86_64.AppImage 
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by ./Nextcloud-2.5.1-x86_64.AppImage)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by ./Nextcloud-2.5.1-x86_64.AppImage)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5DBus.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Xml.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libnextcloudsync.so.0)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libnextcloudsync.so.0)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libocsync.so.0)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5WebEngineWidgets.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5WebEngineCore.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5WebEngineCore.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5WebEngineCore.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Network.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Widgets.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Gui.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Core.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.8' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Core.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Core.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Quick.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5PrintSupport.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5QuickWidgets.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5WebChannel.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.8' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Positioning.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Positioning.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Positioning.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libsnappy.so.1)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.8' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libicui18n.so.55)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.8' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libicuuc.so.55)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Qml.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libQt5Qml.so.5)
./Nextcloud-2.5.1-x86_64.AppImage: /lib/x86_64-linux-gnu/libgpg-error.so.0: no version information available (required by /tmp/.mount_NextclOsHItU/usr/bin/../lib/libgcrypt.so.20)