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 3.0 in the context of the migration.
The Scala 3 compiler is, in itself, a migration tool that can assist you while doing the migration.
No installation required, everything is in the compiler. Discover the Scala 3 Migration Mode.
Scala 3 metaprogramming features are safer, more robust and much more stable than the Scala 2 macro mechanisms. Existing macro libraries will turn out to be much more simple. But it comes at the price of re-implementing the macro methods from the ground up.
In the Migrating Macros section, you will find helpful content to port your macros code to Scala 3.