The document discusses the top Android app development trends for 2021, including Android Instant Apps, MotionLayout, APM and EMM for app performance, Kotlin Multiplatform for code reuse, 5G technology, chatbots, on-demand applications, improved app architecture, Flutter cross-platform framework, blockchain technology, augmented reality, and machine learning. While many new technologies and frameworks emerge, developers should carefully consider factors like expertise, budget, requirements before implementing trends to build effective apps.