docs(updating): add update guide

docs/updating.md

@@ -0,0 +1,58 @@
+# Updating
+
+## v48 to v49
+
+### Update to Angular 21
+
+Update all `@angular/*` packages to Angular 21.
+Follow the [Angular update guide](https://angular.dev/update-guide).
+
+Consider modernizing your application setup by running [Angular migrations](https://angular.dev/reference/migrations).
+Review your eslint setup.
+Use [Siemens Lint](https://github.com/siemens/lint) and avoid disabling rules to catch deprecated Angular constructs.
+
+### Remove deprecations
+
+Remove all deprecated API usages from your codebase.
+Use [@typescript-eslint/no-deprecated](https://typescript-eslint.io/rules/no-deprecated/) to find them.
+
+The v49 schematics cover these removals:
+
+- `si-unauthorized-page` / `SiUnauthorizedPageComponent` migrated to `si-info-page` / `SiInfoPageComponent`
+- `CONFIG_TOKEN` from dashboards replaced by `SI_DASHBOARD_CONFIGURATION`.
+- `ToastStateName` renamed to `StatusType` and relocated to `@siemens/element-ng/common`.
+- `SiMapComponent.onResize` removed entirely; references get stripped.
+
+### Update Element
+
+Update the packages and run migrations:
+
+```sh
+npm i @simpl/brand@3.1.0 # Only for Siemens applications
+ng update @siemens/element-ng@49
+```
+
+Do manual adjustments where needed, especially for the following:
+
+- Review icon usages outside of Element components.
+
+  Always use the correct classes for sizing an icon:
+  - (small: 16px): `<si-icon class="icon-sm" icon="..." />`
+  - (default: 20px): `<si-icon class="icon" icon="..." />`
+  - (large: 24px): `<si-icon class="icon-lg" icon="..." />`
+
+  As the icons new have a reduced built-in margin, spacings must be adjusted:
+  - remove negative margins, which previously were needed to remove the spacing overhead
+  - add extra spacing-1 between icons and inline-text
+
+- Remove the `@angular/animations` package and `@angular/platform-browser/animations` imports
+  if your app never uses the `animations` property in their `@Component` metadata.
+  See our [Motion animation](https://element.siemens.io/architecture/motion-animation/) chapter for more details.
+
+- Compile and test your application. Consult the [changelog](https://github.com/siemens/element/releases/tag/v49.0.0) for more changes.
+
+### Manual updating
+
+1. Update all Element packages to version 49.0.0.
+2. Update `@simpl/brand` to version 3.1.0.
+3. Read the [changelog](https://github.com/siemens/element/releases/tag/v49.0.0) and follow the suggested steps to update your application.

mkdocs.yml

@@ -189,6 +189,7 @@ nav:
     - Resize observer:                    'architecture/resize-observer.md'
     - Theming:                            'architecture/theming.md'
     - UI state:                           'architecture/ui-state.md'
+  - Updating:                             'updating.md'
   - Contributing:
     - Guidelines:                         'CONTRIBUTING.md'
     - Code of Conduct:                    'CODE_OF_CONDUCT.md'