Dating apps are extremely popular, but for the 41 million single, divorced or widowed men and women in the USA over 50, apps targeted for their age can seem dull and boring. Now there's an app called Lumen, the first-ever platform dedicated to the over-50s, with 100% of profiles verified, an emphasis on quality conversations and zero tolerance for ageism. We chat with Lumen co-founder, Charly Lester, about the app that achieved 1 million downloads in only eight months.