The upgrade guide does not cover ng update stopping on a Node.js version message #3786

In an app that is already on Angular 21, ng update @angular/fire@next can stop before it updates anything:

Installing a temporary Angular CLI versioned latest to perform the update.
Node.js version v22.22.1 detected.
The Angular CLI requires a minimum Node.js version of v22.22.3 or v24.15.0 or v26.0.0.

Node.js 22.22.1 is a version Angular 21 supports, so the message is confusing, and docs/version-21-upgrade.md does not mention it.

Why it happens

• ng update chooses which Angular CLI runs the update from the first @angular/ package in the command. If that package has no version number, it downloads @angular/cli@latest.
• @angular/cli@latest is 22.2.1, which requires Node.js ^22.22.3 || ^24.15.0 || >=26.0.0. Angular CLI 21 accepts ^20.19.0 || ^22.12.0 || >=24.0.0.
• On a Node.js version in between, the downloaded CLI refuses to start. This is Angular CLI behavior, and it happens before any AngularFire code runs.

What I ran

On Node.js 22.22.1, on 2026-10-02:

• ng update @angular/fire and ng update @angular/fire@next in an Angular 21 app both stop with the message above.
• ng update @angular/fire@21.0.0-rc.1 in the same app does not.
• The guide's own command, ng update @angular/core@21 @angular/cli@21 @angular/fire@next, is not affected. It ran with a temporary Angular CLI 21.2.24 and completed.

Proposed change

A bullet under "Other notes" naming the message, the cause, and the two ways past it: update Node.js, or give the first @angular/ package a version number.