angular.courses
DIOP0204LibrariesCI gate

View Engine library

The library was compiled with Angular 8 or older (View Engine), which Angular 16+ cannot load.

What it means

Angular 16 removed ngcc, the compatibility compiler that converted View Engine packages at install time. A View Engine library cannot be used at all past Angular 15, whatever its peer range says.

How to fix it

Replace it with a maintained Ivy library, or vendor its source into the application and compile it there.

What it looks like

As printed by diopter check; the UI and the Markdown report show the same finding with its location.

[DIOP0204] `ngx-ancient-widget`@1.4.0 was compiled with Angular 8 (View Engine). Angular 16+ can't load View Engine libraries (ngcc was removed).
In CI
diopter check --fail-on-blockers.
In the UI
The Upgrade plan tab, from diopter next to your dev server, or the static report from diopter build.
For agents
MCP tool check-dependencies (diopter mcp).

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