DailyTech - Tesla Motors Temporarily Shuts Down Production Line for Model X Upgrades Tell me that article is wrong and they aren't offering the 40 kwh battery pack option for the less efficient Model X. I could totally see a 40 kwh option for the Model E and we've already seen it in the Model S (by way of software limiting the 60 kwh pack). But has any site other than dailytech actually mentioned a 40 kwh pack for the Model X before now?
Tesla is no longer making a 40kWh size battery - and even if they were, you wouldn't be required to buy it. You're safe.
The Tesla website has only ever shown 60 and 85 kWh battery options for the Model X, even back when the 40kWh was still an option for the Model S.