This article is a mistake, I got Xenial repos only once. When doing ‘lxrun /uninstall’ and ‘lxrun /install’ again, it’s back to Trusty.

Windows 10 comes with Ubuntu Linux Subsystem but it first started as Ubuntu 14 (Trusty). It is said here users can upgrade to Ubuntu 16 (Xenial):

But, this command doesn’t work with some PCI error:

$ sudo do-release-upgrade -f DistUpgradeViewNonInteractive -d

Anyway, users can still use Xenial repos on Trusty by uninstalling Trusty and reinstall it; open ‘cmd’ console in user mode, not Run as Administrator:

> lxrun /uninstall
blah blah...

> lxrun /install
blah blah...

After reinstalling the Ubuntu Linux Subsystem, it’s still Ubuntu 14 (Trusty):

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.5 LTS
Release:        14.04
Codename:       trusty

$ cat /etc/issue
Ubuntu 14.04.5 LTS \n \l

However, the repos are Xenial repos. On Trusty, users get GCC 4.8; but with Xenial repos, users get GCC 5.4:

$ sudo apt-get install gcc
blah blah...

$ sudo apt-get install g++
blah blah...

$ gcc -v
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2)

$ g++ -v
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2)