From TCB Council,TNC On June 10, 2016 :

It has come to our attention that apparently the installation of the Android Operating System version codename Marshmallow on devices may suddenly make the hotspot feature available to the user, where this feature was unavailable to the user before the installation of this Android OS version.
For devices which were certified with the hotspot feature disabled and the hotspot mode was not tested for compliance, if the installation of the new Android OS suddenly enables the hotspot feature, the manufacturers of these devices will be required to test the hotspot mode for compliance and submit a C3PC application to ISED.