This chapter delves into the intricate world of advanced SQL Server upgrades and migrations, moving beyond simple installations to explore strategies and considerations crucial for modern database environments. In today's dynamic technological landscape, databases need to be not only reliable but also adaptable to changing business needs. This chapter will guide you through crucial planning, execution, and post-migration steps involved in advanced SQL Server scenarios. We also consider how built-in security capabilities like always encrypted and row-level security factor into upgrade and migration planning. We will then explore a variety of upgrade approaches, from side-by-side methodologies to in-place upgrades, evaluating the pros and cons of each. We will also analyze migration strategies from on-premises environments to Azure Cloud, considering the benefits and trade-offs for each. Finally, we will focus on SQL Server to Babelfish for Aurora PostgreSQL migrations and all that it entails. Ultimately, this chapter will equip you with the knowledge and tools to ensure successful, secure, and efficient database upgrades and migrations.