NCCER curricula does 'expire', which means there will be a time where submissions using a particular version of a curriculum title are no longer accepted in the Registry for credentialing.  This takes place five years AFTER the year the new edition is published. As an example, the 4th edition of the Core Curriculum (released in 2009) will expire in 2020 as this is five years after the 5th edition was published in 2015. 


The NCCER website has a current listing of curriculum expiration's here: https://www.nccer.org/docs/default-source/default-document-library/craft_expirations.xlsx?sfvrsn=da41d4f_4.