Update README

Author: mpkorstanje

README.md

@@ -2,4 +2,26 @@
 
 JSON schema for the (legacy) Cucumber JSON format, along with implementation-specific variants from cucumber-jvm etc.
 
-For the new unified message format, see <https://github.com/cucumber/messages>
+* For the new unified message format, see [Cucumber Messages](https://github.com/cucumber/messages).
+* For a tool to convert messages to the legacy json format
+  see [Cucumber JSON Formatter](https://github.com/cucumber/cucumber-json-formatter).
+
+## Implementation Status
+
+These schemas should be considered a best effort work in progress.
+
+These schema was initially implemented and tested as part of
+the [Cucumber JSON Converter](https://github.com/cucumber/cucumber-json-converter). This project does not seem to have
+been used in earnest as the accuracy of the schema leaves much to de desired. The schema is also regression tested in
+the [Cucumber JSON Formatter](https://github.com/cucumber/cucumber-json-formatter) project. This testing is more
+extensive.
+
+| Schema               | Cucumber JSON Converter | Cucumber JSON Formatter |
+|----------------------|-------------------------|-------------------------| 
+| `cucumber-js.json`   | Verified                | Unverified              | 
+| `cucumber-jvm.json`  | Verified                | Verified                |
+| `cucumber-ruby.json` | Verified                | Unverified              |
+| `behave.json`        | Unverified              | Unverified              |
+| `canonical.json`     | Unverified              | Unverified              |
+
+