The T2K experiment observed electron-neutrino appearance in 2012. The results of the combination of T2K data and reactor measurements hint at maximal CP violation. If maximal CP violation is true, electron-antineutrino appearance would be suppressed.
Hence the observation of electron-antineutrino appearance is an important next step, and T2K has been accumulating data with a muon antineutrino beam since 2014. We will discuss the results of the first search for electron-antineutrino appearance in T2K, as well as updated results from T2K's muon-antineutrino disappearance measurements.