As cars increasingly resemble digital devices, a group of technology firms that can send wireless software updates to cars are in hot demand by carmakers scrambling to catch up to Tesla Motors in the arena of over-the-air updates, or OTAs. Interest in the technology, through which certain car functions can be upgraded much the same way as an iPhone, comes as Tesla is set to deliver an OTA for hands-free cruise control this month, allowing its electric Model S sedans to drive themselves on freeways.