Terminology:

The term 2G refers to the second generation of mobile networks. The GSMA has set a certain threshold for technologies to get the label 2G. Examples are: GSM (2G), GPRS (2.5G) and EDGE (2.75G).

Overview

The first 2G network was a GSM network built in 1991 by Radiolinja in Finland. It was the first digital radio network and introduced data services, SMS and MMS. Today, 2G networks have seen their glory days of being the state-of-art technology. Some operators already decommissioned their 2G network or announced to do so within a few years. The main drivers for this is the lack of (high revenue) 2G customers and because they want to use the radio spectrum for their 4G networks. These drivers only hold for innovative markets such as the Singapore and the US.

But...

To offer a reliable service, most operators combine multiple radio technologies. For example, LTE networks only offer data connectivity (some operators offer Voice over LTE). So when you call somebody, your phone probably uses a 2G or 3G network.

But there is more. Many operators hesitate to decommission their 2G networks soon (before 2025). This is because they have contracts with large customers (governments, utility companies, etc) in which they assure a 2G service continuation for years to come. These parties rely on the 2G network for their existing large scale IoT deployments. This explains why some operators are decommissioning their 3G network and leaving their 2G network untouched. And last but not least, there is no good alternative at the moment that can match the pricing and coverage of 2G networks.

Hardware

2G hardware is a perfect fit for IoT deployments with a service life of around 5 years. A lot of different hardware is available and proven. And best of all, the hardware comes at very competitive prices that can make your IoT business case profitable. So before focussing on the new and shiny, give the proven 2G technology a good look. It might solve your technical problems and make your use-case a great return on investment.