Knowledge Base

Guide to the interpretation of version numbers

Qi specifications are numbered with three digits: X.Y.Z. For example 1.0.3

• X is called the major revision number. Specifications with the same major revision number are backward and forward compatible.
• Y is called the minor revision number. A change in minor revision number implies that new requirements are introduced while maintaining backward compatibility previously certified products
• Z is called the editorial revision number. Editorial revisions include clarifications, integrate new transmitter designs into one document (version 1.x series only), and may add new test to the test specifications.
  
  

Current version of the Qi specification

The current version of the Qi specification is version number 2.2.1. This version is available only to members of the Wireless Power Consortium. The Qi specification that is available for public download is version 2.1.

History of the Qi specification

Version 1.0 (July 2010)

• Qi power transmitter delivering 5 watt into a Qi power receiver..
• Choice of power transmitter designs including single coil, coil array, and moving coil power transmitters.
• High flexibility in design of Qi power receivers
• Limited flexibility in the design of Qi power transmitters

Version 1.1 (March 2012)

• Increased design freedom for power transmitters. You can now choose between 12 different power transmitter specifications.
• Increased sensitivity of "Foreign Object Detection". This prevents heating of metal objects near an active transmitter.
• The possibility to power a Qi power transmitter with a USB charger.

Version 1.2 (October 2015)

• Fast charging. The possibility for power transmitters to deliver up to 15 watt and the option for power receivers to obtain up to 15 watt.
• An improved thermal test for power transmitters
• Improved timing requirements
• Changed limits for Foreign Object Detection improve the sensitivity.
• Optional unique identifier for power receivers (WP-ID)

Version 1.3 (January 2021)

• Completely restructured Specification documents with 15 thematic books describing different aspects of the system
• Support for authentication of Qi Certified power transmitters.
• Improved FOD features and testing (including a new low-Q test power receiver)
• Restrictions on the negotiable power levels
• Resolution of mistakes, inconsistencies and ambiguities
• A substantial number of new compliance tests covering the new features as well as features that were not tested in older version of the specification.

Version 2.0 (April 2023)

• Introduction of the Magnetic Power Profile ( MPP )
• Magnetic attachment and alignment of a power transmitter and power receiver
• LQk restrictions on power transmitter and power receiver design
• 360 kHz operating frequency
• Restriction of power receiver communications to real-load modulation
• Detailed magnetic power loss accounting behavior
• New protocol with cloak phase and coupling factor estimation
• Qi v2.0 are not required to be 100% backwards compatible with Qi 1.x Certified Products.

Version 2.1 (September 2024)

• Support for Automatic Alignment Profile (AAP) power transmitters
• Support for Magnetic Accessory Covers – MCPE and MCPM Profiles
• New requirement and test to deal with mechanical obstructions (such as protruding cameras close to the charging area of a phone)

Version 2.2 (April 2025)

• Support for up to 25 watt power transfer
• Power modes optimizing the power transfer to the capabilities of (USB-C) power adapters
• Gain measurement and gain linearization to optimize the power control
• Re-introducing capacitive modulation for power receiver communications
• Improved magnetic power loss accounting
• Mated Q-factor check to verify absence of foreign object before starting the power transfer
• Power loss calibration for FOD above 15 watt power levels