Is anyone a guru on how they work in what appears to be unbranded handsets?

My XZ Dual F8332 which was purchased in Hong Kong and has no operator branding updated from 1 Dec to 1 Feb security patches this morning. This is despite them being out to some variants for a couple of months and the 1 March ones also having been out for over a month.

http://www.xperiablog.net/2017/02/01/sonys-pushes-february-2017-security-patches-to-xperia-xz-x-performance-x-and-x-compact/

http://www.xperiablog.net/2017/03/15/xperia-xz-x-performance-x-and-x-compact-get-march-2017-security-updates/

I presume an operator from the intended region still has to approve an update despite it not being branded to them?

I know I can just flash a different regions firmware . . .