I don't know. When I first registered Lang-8, I was a freshman.Now I'm a postgraduate.So I guess maybe four years. I know Lang 8 corporation developed this mobile phone app in recent years .But I was too lazy to install it on my phone , and I log on Lang-8 website only few times after registration. If there are some improper tones,please forgive me. I really don't know how to interpret my means to you dear helper.