OCaml 5.0.0 introduces a completely new runtime environment with support for shared memory parallelism and effect handlers. As a language, OCaml 5 is fully compatible with OCaml 4 down to the performance characteristics of your programs. In other words, any code that works with OCaml 4 should work the same with OCaml 5. The currently known exceptions to this rule are: the removal of many long-depr