What are Warnings in CPC schemes and when are they used?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Warnings in CPC schemes are used to signal specific information about deviations from the International Patent Classification (IPC) or incomplete classification. The MPEP states, “A warning is used in CPC schemes for signaling deviations from IPC or incomplete classification.“

Warnings in CPC schemes can serve several purposes:

• List IPC groups not included within CPC and indicate the CPC group covering the relevant subject matter
• Indicate the deletion or transferring of CPC groups
• Provide reclassification notices

These warnings are crucial for patent examiners and searchers to understand potential differences between CPC and IPC classifications, as well as to stay informed about changes in the classification system.