At its 25th meeting (2014), the CGPM approved Resolution 1 "On the future revision of the International System of Units, the SI", which sets the path towards a redefinition of four base units at the next CGPM meeting (in 2018). This is a clear step towards the formal adoption of the New SI and its implementation.

Dr Philippe Richard, President of the CCM, and Prof. Joachim Ullrich, President of the CCU, have agreed the timeline for the redefinition, taking into account discussions at the CODATA-TGFC meeting on 3 November 2014 and at Session II of the 103rd CIPM meeting on 13 and 14 November 2014. The resulting "Joint CCM and CCU roadmap towards the redefinition of the SI in 2018" sets dates for the sequence of events leading to the redefinition.

An important date to note is the closing date for the publication of new data to be considered by the CODATA-TGFC for the special adjustment of the fundamental constants in preparation for the redefinition: