450 changes is made in the standard, after input from companies that have been working/works with TOGAF.

TOGAF® 9.1 contains a set of corrections to address comments raised since the introduction of TOGAF® 9 in 2009. The Open Group has been able to address over 400 of the comments received against TOGAF® 9, resulting in over 450 changes to the standard.
 
The maintenance updates in TOGAF 9.1 are based on feedback received on the framework as organizations have put it to good use over the past three years. As such the changes are upwards compatible adding clarification, consistency and additional detail where needed. Some of the most significant updates include:

   The SOA chapter (Part III, Chapter 22, Using TOGAF to Define & Govern SOAs) has been updated to include the latest Open Group SOA Work Group output providing guidance on adapting the ADM phases for SOA

   ADM Phases E and F (Part II, Chapters 13 and 14) have been reworked to match the level of detail in other phases, and the uses of terminology for Transition Architecture, Roadmap, and Implementation Strategy clarified and made consistent

   Corrections have been applied to aspects of the Content Metamodel (Part IV, Chapter 34, The Content Metamodel) including the metamodel diagrams

   The concepts of levels, iterations and partitions have been clarified and made consistent. This includes a reorganization of material in Part III, Chapter 19, Applying Iteration to the ADM and Chapter 20, Applying the ADM across the Architecture Landscape, and also Part V, Chapter 40, Architecture Partitioning

   The terms “artifact” versus “viewpoint” have been clarified and made consistent. This includes a restructuring of Part IV, Chapter 35, Architectural Artifacts

   Changes have been made to improve general usability including:
- The artifacts for each phase are now listed in the phase descriptions
- Duplicate text in several places has been replaced with an appropriate reference
- The “Objectives” sections of the phases have been reworked
- Some artifacts have been renamed to better reflect their usage
 
If you’re already TOGAF® 9 certified,  don’t worry about the status of your certification. The TOGAF® 9 Certification for People Program has been designed to accommodate maintenance updates to the TOGAF® 9 standard such as TOGAF® 9.1. 
 
TOGAF 9.1 is available for online reading at http://www.opengroup.org/togaf/ and available in The Open Group Bookstore at http://www.opengroup.org/bookstore/catalog/g116.htm .
 
A detailed description of the changes between TOGAF 9 and TOGAF 9.1 is available at http://www.opengroup.org/bookstore/catalog/u112.htm .