As it turns out, Belkin appears to be putting its plans to introduce HomeKit compatibility on hold because there is no way to add HomeKit to products that are already on the market. Belkin would need to develop an entire line of new HomeKit-enabled WeMo products, something that the company says it is not interested in doing in at the time being. The information was shared with MacRumors reader Steve on Facebook after he asked about HomeKit.
We've been trying to integrate with HomeKit for sometime, as you know, but as of yet have not found a way to make existing WeMo products work with HomeKit that fall within the Apple guidelines. HomeKit integration requires a specific hardware component - it cannot happen with just a software or firmware update - which means that we would have to make a separate line of HomeKit enabled WeMo products in addition to the ones already out on the market.The WeMo Facebook representative goes on to say that "nothing is off the table" but the company wants to be sure that its product decisions "make sense for the entire WeMo ecosystem" and all current and future users.
This also means that all of the WeMo products you already own still wouldn't work with HomeKit and you would have to buy new ones in order to get compatibility. We have put HomeKit compatibility on hold until we can find a way to make it work for both new and existing users. We are sorry for the disappointing news.
Apple's HomeKit system has specific and stringent security requirements [PDF] that must be included with products that Apple certifies as HomeKit compatible. Existing Belkin WeMo products may not meet Apple's security specifications, which have been described as "bleeding edge."
Apple's demand for strong end-to-end encryption, even for Bluetooth LE, has been citied as one of the reasons why HomeKit-enabled products were slow to roll out to consumers following the mid-2015 HomeKit launch. Unless Apple relaxes its requirements, which seems unlikely, HomeKit compatibility won't come to the WeMo line until Belkin decides to create new HomeKit-enabled products.
With a huge range of WeMo products, from smart outlets and bulbs to cameras and crockpots, already on the market, it's not hard to understand Belkin's reluctance to create all new products and alienate its existing customer base. Some customers using the WeMo line could have hundreds of dollars invested in various products, and for existing customers interested in HomeKit compatibility, all of those items would need to be repurchased.