You can track v5 beta progress in #751
You can install the v5 beta using the next tag: npm add history@next
Changes
In this release the core library was converted to TypeScript, and the type declaration files that are published with the npm package are derived from the source instead of being written by hand. This should make them both more accurate and more useful.
A migration guide will be available soon. For now, you can either browse around the docs on the dev branch or the tests.
Enjoy!