There aren't many CDMA networks in the world, in fact there are only a handful of them and three of them are in the US, while the rest are in Asia. Verizon, Sprint and US Cellular are all CDMA networks - at least when it comes to 3G and 2G connectivity - in the US. With Verizon's LTE network being so far ahead of everyone else's, and their VoLTE network being available to just about everyone, it's about time that CDMA begins its sunset. This way Verizon can re-farm that spectrum for 4G LTE and their upcoming 5G network. Which will give them more bandwidth to handle more users.
According to a report out of FierceWireless, the company is looking to shut down their CDMA 1X network - which handles their 2G or EDGE network - by December 31st, 2019. That gives them just over 3 years to get everyone off of their 2G network. Chuck Hamby, spokesperson for Verizon, said in a statement that "we will not abandon a single customer. We will work with each of the customers one-on-one." Now this isn't so much about getting everyone to upgrade their phone, but making sure that everyone that has coverage, has 3G or 4G LTE coverage where they are. Although in some cases, this may require an upgrade or two, but the majority of Verizon's users are already on 4G LTE devices.
For many, this won't be an issue. However, if you do use Verizon's 2G network at all, you may see that transition on over to 4G LTE in the next few years. Shutting down a network isn't an easy thing, nor something that can be done quickly. While Verizon is currently planning to shut it down on December 31st, 2019, it may be pushed back a few times, due to unforeseen issues with their 2G network, or with customers still using that network.