2.0.0 Migration Guide
Based on this discussion.

Main Points

    angel_diagnostics is deprecated - instead just pass a Logger and set it as app.logger.
    Removed AngelFatalError, and subsequently fatalErrorStream.
      Errors are automatically create 500. Set app.logger to see output.
      angel_errors is no longer useful.
    Removed all @deprecated members.
    Removed @Hooked, beforeProcessed, and afterProcessed.
    Made injections in RequestContext private.
    Renamed properties in AngelBase to configuration.
    Added support for pattern matching and other injections via @Parameter()
    Officially deprecated properties in Angel.
    Fixed a bug where cached routes would not heed the request method. #173
    Reworked error handling logic; now, errors will not automatically default to sending JSON.
    Removed the onController stream from Angel.
    Controllers now longer use call, which has now been renamed to configureServer.


Aside from these points, there are several things to note.
Migration in itself will be pretty easy to achieve. Plugins and services haven't really changed, it's just the HTTP server itself.

What should I use instead of X?

In 1.1.0, the following were completely removed:
      There is no replacement for before/after. This way, it is easier to keep track of the order request handlers run. responseFinalizers are still in place.
      justBeforeStart, justBeforeStop => startupHooks, shutdownHooks
      fatalErrorStream is no longer necessary; you can just set app.errorHandler. Fatal errors will be wrapped in a 500 response.

How should I define global middleware?

app.use((req, res) => ...)
Much cleaner in 1.1.0. 😄