Wileyfox Zen & TruCaller
I made coment on Wileyfox Zen feedback and got a response from Yandex.Apparently they might include a way to disable it in a future update but as yet you have no option. Wileyfox say they will include a way to disable it in the next update to be installed in the next few weeks, however, in view of Yandex response I wouldn't hold your breath.
All services (seems to be related to 'Trebuchet') for this are hidden and no permissions are available to prevent it data slurping. The only solution found was to restrict all background data and net access via a non-root firewall app such as Mobiwol. Some basic investigations reveals that data does flow to Yandex out of the box and that you can not opt out. The lack of optout implies you automatically consent to its activities (is this this modern version of 'Shrinkwrap Licensing?) contrary to the provisions in law which requires prior knowledge or optout provision.
As for Trucaller, there are numerous issues such as what they say they won't do yet in their EULA & Privacy statement clearly contradict themselves. Out of the box it is next to useless without signing up. For example, you can not access SMS if you don't agree. This is being replaced.
We run dozens of these devices for vulnerable people for whom release of sensitive PII is a serious issue.
Apart from the Storm trialled last year ( (in repair for 42 weeks out of 52) we have had, until now, no issue with the Swift series. Consequently it is hope that they get back on track as until we can establish the same control as before, we will not be buying any further units.