Lenovo's Tech World conference has been a barrage of news, including the official announcement of the Moto Z family, all compatible with modular accessories called Moto Mods. With some of these mods, such as a projector, being fairly involved and likely expensive, it would be a real bummer if you had to leave them behind whenever you eventually upgraded from your Moto Z. Thankfully, a press release from Motorola confirms this isn't the case, and that current Moto Mod modules will be perfectly compatible with Moto Z phones released in the future, though some third-party ones may end up requiring software upgrades.
Since Lenovo is using a high-fidelity, high-speed proprietary connection for these mods that will allow them to essentially hook into the system as if they were built into the phone, it's easy to assume that a lot of man-hours from the engineering team went into designing the connector, testing it and making it work, as well as creating the initial mods for it to nail the format. Moto and Lenovo would have to do all of that work again when the new flagships come out if the mods were essentially disposable, making this move just as good for them as it is for consumers. This could also mean that future mods will be backwards compatible with the first-gen Moto Z family, but, like anything else regarding backwards compatibility in the tech world, nobody should be holding their breath on that one.
It's worth a mention that the only competitor on the market right now with modular capabilities, the LG G5, may not have the same benefit. LG has yet to say if the LG Friends will be compatible with the G6 and onward, or even if they're committed enough to a modular design to include the capability in their next flagship at all. The other hopeful competitor, Project Ara, has yet to hit the market and, according to a demo at Google I/O this year, sports a large number of fixed components, leaving it up in the air as to whether first-gen mods will work on newer models and vice versa.