The Best Ways to Update IoT Devices Over-the-Air

As the Internet of Things (IoT) continues its march across the world, manufacturers have embraced new ways to remotely and reliably update devices in the field. Considering there are forecast to be more than 41 billion connected IoT devices by 2025, keeping them updated with the latest software and firmware is essential.

That’s where over-the-air (OTA) updates come in. OTA update refers to the practices of remotely updating the software or firmware of a connected IoT device. This saves IT staff time and effort as they can push updates to a fleet of devices at once. 

Let’s take a closer look at how OTA updates are done and the guidelines you should follow to ensure it happens smoothly and efficiently.

Ways to Update IoT Devices OTA

There are three main methods to update IoT devices OTA, no matter how many devices you’re updating in the fleet. 

1. Edge-to-Cloud OTA Updates

With this method, the IoT device is connected to the Internet and receives the update from a remote server directly. The device can handle updates to both its firmware and the software it runs. Most consumer IoT devices are updated this way because they are close to Wi-Fi signals in people’s homes and small commercial locations.  

Update Method Example: Amazon Echo Dot update, Google Home update, Nest thermostat update

2. Gateway-to-Cloud OTA Updates

With this method, the update is sent to an Internet-connected gateway, which is responsible for managing a fleet of IoT devices. The gateway’s firmware, any or all of the software running on it, and the software application’s host environment can all be updated in this scenario. The IoT devices themselves remain unchanged. This method is useful for simpler IoT devices that do not have a lot of computing power, nor are they Internet-enabled. They can be protected from outside signals and intrusion by the gateways, which is why the finance and healthcare industries favor this method.

Update Method Example: Banking and financial services IoT devices that monitor the supply of cash in bank branches, ATMs, bank partners, and more. 

3. Edge-to-Gateway-to-Cloud OTA Updates

With this method, the firmware and software applications on IoT devices are updated via the Internet-connected gateway that controls them. Unlike the previous scenario, the gateway is not updated at this time. This method is useful in scenarios where hardwire access to the Internet, or the gateway is limited. 

The IoT devices must have enough computing power to accept a connection from the gateway and perform the update on itself, but do not necessarily need Internet connectivity. The gateway is the only Internet-connected device in the network and delivers the updates to the devices as required. 

Update Method Example: Field-based sensors in agricultural settings that monitor soil moisture levels, weather conditions, and automated cultivation machine performance. 

Each method has benefits and drawbacks, so the one you choose depends on a variety of factors, including, but not limited to: 

• Internet connectivity
• IoT device and gateway technical details
• Wi-Fi capability
• Network security requirements and capabilities

Considerations For Your IoT Device OTA Update Method

There are a few considerations IoT experts recommend thinking about when choosing your update method.

1. Automatic recovery from corrupted or interrupted updates: Your updates should be able to roll back gracefully if they don’t succeed completely. The devices should be able to roll back to the previous stable version without manual intervention (or at least limited manual work) and then signal the update issue to IT staff. 
2. Update integrity checks: Devices should only ever download and install verified updates, which should happen automatically. The device should look for a verification certificate, code, or something else proprietary within the code that indicates it is a valid update and that it should proceed. 
3. Secure communication channels: All OTA updates should be done over encrypted communication channels, including all external connections between the cloud, gateway, and Internet, as well as the internal ones between a gateway and the IoT fleet. 
4. Allow partial updates: Depending on the frequency your devices are connected for updates, you may want to allow partial updates at any given time as well. This would decrease bandwidth consumption and on-device processing time, making it easier to update even the most isolated devices.

With all the IoT devices being deployed globally, we’re going to need to develop more efficient ways of updating them. With OTA updates, you can keep your entire IoT fleet updated, no matter where they’re located or what industry you’re in.