[Venue 7840] Disable firmware update checking/notifications

I recently received a replacement for my Venue 7840 which DELL's support team had concluded had defective hardware. I now have a new one without Lollipop. For me, this is a good thing. My problems seems to have started with the update, however I only really had it for a day before downgrading to Lollipop. I would like to put off the upgrade to Lollipop for at least a week this time. How would I go about doing that?