The specification provides two main features for use with the internationalized domain names specification released in August 2010 (IDNA2008):
- A comprehensive mapping to reflect user expectations for casing and other variants of domain names. This mapping is allowed by IDNA2008, and follows the same principles as in the previous version of that specification (IDNA2003). It thus provides users consistency between old and new versions.
- A compatibility mechanism that supports internationalized domain names valid under the IDNA2003 specification and the IDNA2008 specification. This second feature allows browsers, search engines, and other clients to handle both old and new domain names during the transitional period until registries update their rules to follow IDNA2008.