Thank you so much for the article, well documented and explained. i bookmarked it to come back to it once I'm off the clock.
I have a secondary phone I use because of battery life (2 weeks) and multiple sim setup (it's an LG A290). I have had this phone for about 2 years now and for the past couple months a notification message kept popping in. It says:

Secure time Expired

I'm not a paranoid freakezoid and I'm not doing anything wrong (illegal) so I'm not worried about my data being somewhere in a pile of others but I have a weird feeling about it to say the least.