What is the difference between LTE Cat NB1 and LTE Cat NB2?

LTE Cat NB1, also known as Narrowband IoT (NB-IoT) is a Low Power Wide Area (LPWA) technology that has been developed to enable a wide range of devices to be connected to the internet using existing mobile networks. NB-IoT has been developed to enable the Internet of Things (IoT). It is a low power, narrowband technology that can support small amounts of 2-way data transmission in an efficient, secure, and reliable manner. This standard was created in 3GPP Release 13.

LTE Cat NB2 is an upgraded version of the LTE Cat NB1 standard (NB-IoT). In Release 14, 3GPP introduced an enhanced NB-IoT protocol and a new device category called NB2. This standard is an upgraded version of the LTE Cat NB1 standard.

LTE NB1 vs LTE NB2