When I update Ubuntu from 16.04 to 18.04, there is a flood of errors:
$ sudo apt update && sudo apt upgrade
Hit:1 http://ubuntu.ntc.net.np/ubuntu bionic InRelease
(appstreamcli:30076): GLib-CRITICAL **: 20:36:32.027: g_strchug: assertion 'string != NULL' failed
(appstreamcli:30076): GLib-CRITICAL **: 20:36:32.027: g_strchomp: assertion 'string != NULL' failed
corrupted double-linked list
Aborted (core dumped)
Reading package lists... Done
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh > /dev/null; fi'
E: Sub-process returned an error code
Also, when I check my Ubuntu version, it shows 18.04 in terminal, but in startup it shows 16.04. How to resolve this?
