The date is unknown as of yet. Usually, if everything goes well with the new firmware version, it is installed in the newly produced devices approximately 2-3 weeks after the firmware release. However, there is no guarantee that it will happen with the current latest version. It might be that the production will skip the 7.3 version and will install the upcoming 7.3.1 version later on (which should be out in 1-2 weeks from now). Hence, it should not take long. However, when will the newly bought devices will have the latest firmware also depends on how many stocked devices with previous versions your reseller still has in store.