The document discusses 5 ways that code can still be stuck in the 1990s and provides solutions to modernize it. Specifically, it addresses issues with 1) implicit messaging between systems, 2) complex threading code, 3) overuse of remote procedure calls, 4) abuse of garbage collection, and 5) over-reliance on logging without metrics. The solutions proposed are to use explicit contracts between systems via message passing, break operations into stateless and stateful "actors", embrace failure of remote systems, understand garbage collection behavior, and instrument code with metrics for monitoring.