Migrate your existing SPFx solution to the new HEFT-based toolchain.
New SPFx-apps solutions should use the latest SharePoint Framework version. The latest SPFx version (1.22.* blog from 22.02.2026) introduced a new toolchain based on HEFT instead of Gulp (see my blog post: SPFx-Framework v1.22 - Rush Stack, Heft & Webpack-based toolchain - First try ). This means that existing projects must migrate the typical SPFx libraries, and in addition, the toolchain also needs to be updated. The migration path is explained in the Microsoft learn article: Migrate from the Gulp-based to the Heft-based Toolchain In the following blog post I describe my steps and experience with the migration process. For this demonstration, I've migrated an existing SPFx web part from 1.21.1 to 1.22. At first I checked if I had installed the SPFx 1.22 version already. I did this with: npm ls -g --depth=0 After I verified that the new version is available, I continued with the first step regarding the official documentation. I uninstalled the Gulp toolchain dependen...