How can I migrate a small gulp-based build to a newer version without causing downtime during development?

Moving a small application that relies on gulp for its build process to a newer gulp release while keeping the development environment available.

The migration must preserve existing task definitions, especially those that use gulp.watch for live reloading, and avoid any interruption in the watch‑based workflow.

Uncertainty remains about how changes in the gulp API affect task registration with gulp.series or gulp.parallel, and whether the updated version continues to support the same plugin interfaces.

What steps ensure that existing gulp.watch tasks remain functional after the upgrade? How can the new gulp version be validated in a staging setup without affecting the current workflow? Are there any breaking changes in the gulp API that impact task composition with gulp.series or gulp.parallel?