Scala breaks binary compatibility approximately every 2-3 years, which is fast by JVM standards but slow compared to most programming languages (e.g. Python releases an incompatible version every 1-2 years). You can blame Scala for at most one incompatibility in that long list; older versions of Scala are incompatible with Java 9+ (this is true for many JVM frameworks too, as Java 9 made breaking changes).