Overview of the Different Versions of the I2C Specification

The very first specification dates back to the year 1982. It only covered Standard mode (up to 100 kbit/s) and 7-bit addressing. Extensions like Fast Mode, Hs-Mode or 10-bit addressing were added in later versions.

Version 1.0 - 1992

This version of the 1992 I2C-bus specification included the following modifications:

Version 2.0 - 1998

As the I2C-bus became a de facto world standard implemented in over 1000 different ICs and licensed to more than 50 companies, an update of the specification became necessary as many of the newer applications required higher bus speeds and lower supply voltages. This version 2.0 of the I2C-bus specification met those requirements and included the following modifications:

Version 2.1 - 2000

Version 2.1 of the I2C-bus specification is the most current version. It includes the following minor modifications: