That version is the first version to introduce fully-fledged support for ES Modules (see Modules: ECMAScript modules). It's also three years old, which provides quite a fair bit of backwards compatibility.
The usage of TypeDI++ with versions older than 15.3.0 may be achieved via external packages such as ESM, though this would not be an officially supported scenario, and any issues caused as a result of the old Node version would not be fixed.