The Electron Capture in ${}^{163}$Ho experiment

The goal of the Electron Capture in ${}^{163}$Ho (ECHo) experiment is the determination of the electron neutrino mass by the analysis of the electron capture spectrum of ${}^{163}$Ho. The detector technology is based on metallic magnetic calorimeters operated at low temperature in a reduced background environment. During the first phase of the experiment, ECHo-1k, the detector production has been optimised and the implantation process of high purity ${}^{163}$Ho source in large detector arrays has been developed. The implanted detectors have been successfully operated and characterised at low temperatures, reaching energy resolution below 5 eV. High statistics and high resolution ${}^{163}$Ho spectra have been acquired and analysed at the light of the new developed theoretical description of the spectral shape, considering the independently determined value of the energy available to the EC process, Q${}_{EC}$, and a dedicated background model. In this contribution, we present preliminary results obtained in the first phase of ECHo. At the same time we discuss the necessary upgrades towards the second phase of the experiment, ECHo-100k. In particular, we focus on the production of large arrays with ${}^{163}$Ho embedded in the absorbers and on the multiplexed readout.