Hydrogen can play a key role, as a resource for industrial processes, a fuel for transportation, and a vector for high-capacity and/or long-distance electricity storage [1]. A sharp increase in the share of hydrogen in the overall European energy mix is expected, with a value reaching 13-14% in 2050 against less than 2% currently [2]. In this context, it will be necessary to increase the production capacity of carbon-free hydrogen, primarily through water electrolysis. At European level, a deployment plan for 100 GW of electrolysis is thus proposed by 2030, allowing during its operation to produce 10 million tons of hydrogen per year, to which are added an additional 100 GW for export [1]. However, the production of carbon-free hydrogen is currently not competitive with conventional production routes from fossil fuels (methane steam reforming in particular). The deployment of high-power electrolyzers is likely to significantly lower the cost of the hydrogen produced. But the efficiency of the electrolysers is also a key parameter towards the Levelized Cost of Hydrogen (LCOH). From that perspective, Solid Oxide Electrolysis (SOE) presents the highest efficiency and is therefore considered to be an highly promising technology to produce hydrogen at low cost [3-4]. In addition, it still has a significant potential for innovation, making it possible to gain in performance and lifetime. To reach large electrolysis plants, the upscaling of the different components of the SOE technology is a cornerstone, which includes cells, stacks and modules. The status of development of the technology will be presented, as well as the remaining challenges. The current R&D developments performed to meet those challenges will be detailed.