Adobe Flash is dead. As of December 2020, all major browsers removed Flash support entirely. But thousands of Flash applications - educational tools, training simulations, interactive exhibits, and games - still have value. Their content is relevant. Their audiences still exist. Only their technology is obsolete. During our founder's previous tenure at a development agency, we led the migration of The Great Fire of London - an educational game originally built for the Museum of London - from Flash to HTML5. The kicker? The original source code was lost. That project taught us a comprehensive methodology for Flash-to-HTML5 migration that we now apply through our legacy modernisation service . This guide covers the full process. Step 1: Assess What You Have Before writing any code, audit the Flash application thoroughly.…