LTE UE Categories were a popular topic once upon a time. I have various blog posts on the topic, the earliest one being in 2009 , then in 2011 and 2015 . Most of the smartphones started with Category 3 (Cat-3), going on to Cat-6, Cat-9, etc. Cat-2 was never used as far as I know. Cat-1 and Cat-4 gained popularity in various IoT applications. The picture above from this press release , nicely summarises the evolution of various 3GPP technologies, including IoT. As you will notice, an updated version of LTE Cat-1 known as Cat-1bis was in 3GPP Release-13. You will also notice that LTE Cat-0 was introduced in Release-12 that evolved into eMTC or LTE-M (Cat-M1). A blog on Ericsson has a nice summary here . In Release-13, LTE Cat-1bis was introduced. This article explains what Cat-1bis is and how's it different from Cat-1: LTE Cat 1, sometimes also refers as 4G Cat 1, is specifically designed for more feature-rich Machine-to-Machine (M2M) IoT applications. The technology was initially
2G, 3G, 4G, 5G, 6G, Wi-Fi, IoT, Bluetooth, LoRaWAN, Sigfox, Satellites