diff --git a/docs/connectors/kafka.md b/docs/connectors/kafka.md
index 415b8520..90eb0dc9 100644
--- a/docs/connectors/kafka.md
+++ b/docs/connectors/kafka.md
@@ -13,6 +13,34 @@ The `streamfusion-kafka` connector extension and the matching `streamfusion-*` f
 must both be installed. A missing extension is a planner fallback, never a linkage failure. See
 [Deployment](../deployment.md).
 
+## Flink release lines
+
+Each Flink line selects the Kafka connector release published for it, together with the Kafka
+client that connector was built against.
+
+| | Default build | `flink-1.18` build |
+| --- | --- | --- |
+| Flink | 2.2.1 | 1.18.1 |
+| Kafka connector | `flink-connector-kafka:5.0.0-2.2` | `flink-connector-kafka:3.2.0-1.18` |
+| Kafka client | 4.2.0 | 3.4.0 |
+
+Pinning the client matters because a direct dependency is needed for source compilation, and
+naming another version silently overrides the connector's transitive client and changes producer
+semantics.
+
+`3.2.0-1.18` is built against Flink **1.18.0** while the StreamFusion 1.18 build targets
+**1.18.1**, and it is the final Kafka connector release published for the 1.18 line. Later
+connector releases target 1.19 and newer, so Kafka fixes do not reach this line. That combination
+is admitted deliberately rather than by default: it is exercised on every change by the
+`streamfusion-kafka` module suite under `-Pflink-1.18`, and by Flink's own unchanged
+`DynamicKafkaTableITCase`, `KafkaChangelogTableITCase`, `KafkaTableITCase` and
+`UpsertKafkaTableITCase` running against real brokers in the upstream `kafka` suite on the 1.18
+line. Both prove native execution rather than only passing.
+
+Because Flink owns every broker interaction, a Kafka defect on this line is fixed by the
+connector, not by StreamFusion. Deployments that need a newer Kafka connector need a newer Flink
+line.
+
 ## Source: Flink consumption, native decode
 
 Flink continues to own topic enumeration, split assignment, offsets, checkpoints, authentication,
diff --git a/docs/flink-compatibility.md b/docs/flink-compatibility.md
index e362e05e..dbb8d00a 100644
--- a/docs/flink-compatibility.md
+++ b/docs/flink-compatibility.md
@@ -46,6 +46,10 @@ Install one complete line; a mixed install is an error.
 Both payload lines use the host's SLF4J 1.7 API and binding; it does not bundle Arrow's transitive
 SLF4J 2 API into Flink's global classpath.
 
+The 1.18 Kafka connector is the one dependency whose own target differs from the line it is used
+on: `3.2.0-1.18` is built against Flink 1.18.0 and is the last release published for that line.
+[Kafka](connectors/kafka.md) records what that admits and how it is verified.
+
 The Kernel-based Delta implementation belongs only to the 2.2 source root and does not enter
 the 1.18 compilation, Javadoc or source artifacts. There is no admitted native Delta connector on 1.18 yet. Do not build or install a 1.18 Delta payload;
 this is unavailable functionality, not a verified host fallback.