How do I manage users on my HTC One with Android 5?
Warning: This solution requires a rooted device.


Download the Xposed Framework installer by opening this link on your device: http://repo.xposed.info/module/de.robv.android.xposed.installer
Alternatively, scan this QR code.
Install and open the Xposed Installer app.
Enter the 'Framework' section, select 'Install/Update' then reboot your phone.
Once you've rebooted, open the Xposed Installer again.
Enter the 'Download' section, and search for 'Multiple Users'.
Select 'Multiple users for phone'.
Swipe right to the 'Versions' tab and select 'Download' on the newest version of the module (which will be shown at the top of the list).
Wait up to two seconds until a popup appears.
Select 'Install' and wait another two seconds.
Select 'Done' (not 'Open') and change from the 'Download' section to the 'Modules' section.
Tick the checkbox beside 'Multi Users'.
Reboot your device.
Open 'Settings' and go down to the 'Users' option, which will now be there.