This book constitutes contributions of the ISoLA 2021 associated events. Altogether, ISoLA 2021 comprises contributions from the proceedings originally foreseen for ISoLA 2020 collected in 4 volumes, LNCS 12476: Verification Principles, LNCS 12477: Engineering Principles, LNCS 12478: Applications, and LNCS 12479: Tools and Trends.

STRESS - Introduction.- An Introduction to Graphical Modeling of CI/CD Workflows with Rig.- Pyrus: an Online Modeling Environment for No-Code Data-Analytics Service Composition.- Integrating External Services in DIME.- Asking Why.- Formal Methods for a Digital Industry: Industrial Day at ISoLA 2021.- Agile Business Engineering: From Transformation Towards Continuous Innovation.- Towards Living Canvases.- Use Cases for Simulation in the Development of Automated Driving Systems.- Simulation-based Elicitation of Accuracy Requirements for the Environmental Perception of Autonomous Vehicles.- DSLs and Middleware Platforms in a Model-Driven Development Approach for Secure Predictive Maintenance Systems in Smart Factories.- From Requirements to Executable Rules: An Ensemble of Domain-Specific Languages for Programming Cyber-Physical Systems in Warehouse Logistics.- Mining Data Quality Rules for Data Migrations: A Case Study on Material Master Data.- Programming - What is Next?.- Low-Codeis Often High-Code, So We Must Design Low-Code Platforms to Enable Proper Software Engineering.- Time for All Programs, Not Just Real-Time Programs.- Integrated Modeling and Development of Component-Based Embedded Software in Scala.- Slang: The Sireum Programming Language.- HAMR: An AADL Multi-Platform Code Generation Toolset.- Fundamental Constructs in Programming Languages.- Introducing Dynamical Systems and Chaos Early in Computer Science and Software Engineering Education can Help Advance Theory and Practice of Software Development and Computing.- GATE: Gradual Effect Types.- Fixing Classification: A Viewpoint-based Approach.- The Future of Programming and Modelling: a Vision.- Towards Model-based Intent-Driven Adaptive Software.- The Interoperability Challenge: Building a model driven Digital Thread platform for CPS.- Programming vs. That Thing Subject Matter Experts Do.- Aligned, Purpose-Driven Cooperation: The Future Way of System Development.- RAILS: Roadmaps for AI integration in the raiL Sector.- A Journey through Software Model Checking of Interlocking Programs.- Supporting the Development of Hybrid ERTMS/ETCS Level 3 with Formal Modelling, Analysis and Simulation.- Formal Methods in Railway Signalling Infrastructure Standardisation Processes.- sVerify: Verifying Smart Contracts through Lazy Annotation and Learning.- Verifying temporal properties of stigmergic collective systems using CADP