How reliable is semantic versioning? How easy is it to assess if a new version of a dependency will break your application? In a world where upgrading dependencies is a regular and urgent activity it’s important to be able to assess the likelihood of things not going well. Semantic versioning is one tool to help but like all contracts it relies on an understanding between producer and consumer about what upward compatibility means.

In this session we’ll explore the technical aspects of upward compatibility: what can you tell by analysing java classes, what tools are there to help. How you can write code to minimise your exposure or help consumers have a better experience.

And, since theory is not enough, well explore at what the wisdom of the crowds tells us about upward compatibly in practise; we’ll look at data from Maven Central and other places to see just how good the code out there is in being upwardly compatible and honest about semantic versioning.