doc: add notes for websocket apis in ring 1.12

README.md

@@ -25,7 +25,8 @@ version works for your stack, check the version matrix below.
 
 | rj9a | Jetty | JDK | Clojure | Servlet API | Ring API | Maintained? |
 | --- | --- | --- | --- | --- | --- | --- |
-| HEAD | 12.0.x | 17 | 1.11 | N/A | 1.11 | true |
+| HEAD | 12.0.x | 17 | 1.11 | N/A | 1.12 | false |
+| 0.32.x | 12.0.x | 17 | 1.11 | N/A | 1.11 | false |
 | 0.30.x | 12.0.x | 17 | 1.11 | N/A | 1.10 | false |
 | 0.22.x | 11.0.x | 11 | 1.11 | Jakarta 5.0 | 1.10 | true |
 | 0.17.x | 10.0.x | 11 | 1.10 | Jakarta 4.0 | 1.9 | false |
@@ -37,6 +38,12 @@ releases on [branch
 `jetty-11`](https://github.com/sunng87/ring-jetty9-adapter/tree/jetty-11) which
 is based on Jetty 11.
 
+Note that from 0.33 of rj9a, we dropped dependencies to `ring/ring-core` and
+only depend on their protocol artifacts. This won't be a problem if your
+applications are just normal ring sync or async handlers. However, for websocket
+users, you will need to include `ring/ring-core` explicitly as dependency to be
+able to use websocket APIs.
+
 For JDK 8 users, `0.14` releases should be usable but I'm no longer actively
 maintaining it.