From the early days of aviation training to today’s advanced learning ecosystems, e-learning standards have shaped how digital education is built, shared, and tracked. This multi-series explores the evolution of those standards: from AICC, which pioneered interoperability in the 1980s, to SCORM 1.2, which standardized content packaging and communication, to SCORM 2004, which introduced sequencing rules and stronger consistency across LMS implementations, to xAPI, which enabled activity tracking beyond the browser, and to cmi5, the modern bridge that connects structured e-learning with the flexibility of xAPI. Each post unpacks the technical foundations, workflows, and real-world impact of these standards, helping developers and learning professionals understand not just how they work but why they still matter.