Currently, our SPFx project upgrade command only updates spfx-fast-serve-helpers up to SPFx version 1.15.2. However, according to the fast-serve documentation, the helper package should always match the SPFx minor version (not the patch version), and this pattern has been in place since v4.

“The migration is as easy as just changing the version of spfx-fast-serve-helpers in your package.json to match the corresponding SPFx minor version (do not change the patch version).”

What needs to change

We should extend our upgrade logic to ensure that:

• spfx-fast-serve-helpers is included in upgrade steps for all supported minor SPFx versions beyond 1.15.2.
• The version set matches the SPFx minor version (e.g. for SPFx 1.17.3 → use new FN002019_DEVDEP_spfx_fast_serve_helpers('1.17.0'),).