Scala 3 has been carefully designed to improve the backward and forward compatibility of the Scala programming language.
In the Compatibility Reference you will learn about the compatibility between Scala 2.13 and Scala 3 in the context of the migration.
The Scala 3 compiler is, in itself, a powerfull migration tool that can assist you during the transition from Scala 2.13 to Scala 3.
Learn about the migration features of the tooling ecosystem in the Migration Tools section
Scala 3 provides a toolbox full of metaprogramming features, which are safer, more robust, and much more stable than their counterparts in Scala 2. Implementing macro libraries in Scala 3 is simpler and the resulting libraries are easier to maintain across future versions of Scala. The improvements come at a price: existing macro libraries need to be re-implemented.