Portugal NHR requirements

Hi guys, quick question as I am in the process of going down the NHR route as an EU citizen (Irish) - does anyone know if I now require a 1 year rental contract to satisfy the requirements for NHR? I hear people saying they managed it with a 6 month contract but I was of the understanding that an offical contract under Portuguese law would need to be for 1 year. Would appreciate it if someone could clarify this for me. Many thanks!