The development of ISO/IEC 20000 began in the UK with the IT Service Management Forum (itSMF) funding and supporting the development and launch of the British Standards Institute (BSI) BS15000 in 2000. In 2005 BS15000 was superseded by what we refer today as ISO/IEC 20000. The International standard is founded around the Information Technology Infrastructure Library or ITIL as it is more often referred to. The development of the standard was based around ITIL version 2, which has or being superseded by ITIL version 3.
ITIL version 3 seems to be slowly being adopted by the IT industry, potentially due to the slow delivery of the accompanying training courses that assist with educating the IT community as to the virtues of version 3. The merits and processes of ITIL version 2 we are informed, have been absorbed into ITIL version 3.
Almost a year after the launch of ITIL version 3 we have not witnessed any rush to update the ISO/IEC 20000 standard with any significant changes. So it maybe safe to assume that ISO/IEC 20000 will continue to be based upon ITIL version 2.