docs: explain jackson compat in readme

Author: stainless-app[bot]

README.md

@@ -291,6 +291,17 @@ both of which will raise an error if the signature is invalid.
 Note that the `body` parameter must be the raw JSON string sent from the server (do not parse it first).
 The `.unwrap()` method can parse this JSON for you.
 
+## Jackson
+
+The SDK depends on [Jackson](https://github.com/FasterXML/jackson) for JSON serialization/deserialization. It is compatible with version 2.13.4 or higher, but depends on version 2.18.2 by default.
+
+The SDK throws an exception if it detects an incompatible Jackson version at runtime (e.g. if the default version was overridden in your Maven or Gradle config).
+
+If the SDK threw an exception, but you're _certain_ the version is compatible, then disable the version check using the `checkJacksonVersionCompatibility` on [`OrbOkHttpClient`](orb-java-client-okhttp/src/main/kotlin/com/withorb/api/client/okhttp/OrbOkHttpClient.kt) or [`OrbOkHttpClientAsync`](orb-java-client-okhttp/src/main/kotlin/com/withorb/api/client/okhttp/OrbOkHttpClientAsync.kt).
+
+> [!CAUTION]
+> We make no guarantee that the SDK works correctly when the Jackson version check is disabled.
+
 ## Network options
 
 ### Retries

orb-java-core/src/main/kotlin/com/withorb/api/core/Check.kt

@@ -73,6 +73,8 @@ This can happen if you are either:
 2. Depending on some library that depends on different Jackson versions, potentially transitively
 
 Double-check that you are depending on compatible Jackson versions.
+
+See https://www.github.com/orbcorp/orb-java#jackson for more information.
         """
             .trimIndent()
     }