---------- Post added at 08:40 PM ---------- Previous post was at 08:28 PM ----------
I think there a very simple way to enable the Multiusers functionality in this device, and i already used it and worked perfectly.
(My device is sony xperia z1, android 4.4.4, stock rom, rooted and deodexed):
Step 1: Install GravityBox Module (last version).
Step 2: Enable Lock Screen Rotation : go to the GravityBox settings menu then under Status bar tweaks --> QuickSettings Management then enable the "lock screen rotation".
Step 3: add this line to your "build.prop" (or use any build.prop editor from the play store):
Step 4: REBOOT.
After that you will see a new entry in your system setting called "users" which you can add and/or edit your user profiles.
And when you rotate your lock screen you will see all your profiles to be changed directly from the lock screen.