T2K is a long baseline neutrino experiment situated in Japan. T2K has established CP violation in the lepton sector on a 2$\sigma$ confidence level. To improve this result to better than 3$\sigma$ confidence level, the T2K collaboration proposes to continue the data taking beyond 2021 and to upgrade both, the neutrino beam as also the T2K near detector. The detector upgrade consists in the installation of 3 new subdetectors in the existing near detector: A Super Fine Grain Detector acting as neutrino target, 2 high angle Time Projection Chambers and a Time of Flight detector. In this article, the R\&D efforts of the T2K ND Upgrade Working Group towards these new subdetectors are summarized. Also, an outlook on the plans beyond 2026 is given.