At this time the available tag numbers in the user defined range of 5000 to 9999 have all been allocated. In December 2009 the Global Technical Committee Governance Board approved the use of tag numbers in the 20000 to 39999 range for use as user defined tags to be used bilaterally between parties. These tags do not need to be registered. The Global Technical Committee (GTC) Governance Board recommends that fields/tags and enumeration values from later versions of FIX which meets the business or implementation of FIX be retro-fitted into the implementation.