> The JS-based codebase will continue development into the 6.x series, and TypeScript 6.0 will introduce some deprecations and breaking changes to align with the upcoming native codebase.
> While some projects may be able to switch to TypeScript 7 upon release, others may depend on certain API features, legacy configurations, or other constraints that necessitate using TypeScript 6. Recognizing TypeScript’s critical role in the JS development ecosystem, we’ll still be maintaining the JS codebase in the 6.x line until TypeScript 7+ reaches sufficient maturity and adoption.
It sounds like the Python 2 -> 3 migration, or the .Net Framework 4 -> .Net 5 (.Net Core) migration.
I'm still in a multi-year project to upgrade past .Net Framework 4; so I can certainly empathize with anyone who gets stuck on TS 6 for an extended period of time.