diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3b1fc83d..a5499d51 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,7 @@ name: "CI"
 on: [push, pull_request]
 
 env:
-  FLINK_TAR_URL: "https://s3.amazonaws.com/flink-nightly/flink-2.0-SNAPSHOT-bin-scala_2.12.tgz"
+  FLINK_TAR_URL: "https://s3.amazonaws.com/flink-nightly/flink-2.1-SNAPSHOT-bin-scala_2.12.tgz"
 
 jobs:
   ci:
@@ -27,7 +27,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java_version: [ 8, 11, 17, 21 ]
+        java_version: [ 17, 21 ]
     steps:
       - uses: actions/checkout@v4
       - name: "Build images"
diff --git a/testing/docker-test-job/pom.xml b/testing/docker-test-job/pom.xml
index 6c6185f1..c52eb94b 100644
--- a/testing/docker-test-job/pom.xml
+++ b/testing/docker-test-job/pom.xml
@@ -27,7 +27,7 @@ under the License.
 
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-		<flink.version>1.9.0</flink.version>
+		<flink.version>1.20.0</flink.version>
 		<java.version>1.8</java.version>
 		<scala.binary.version>2.11</scala.binary.version>
 		<maven.compiler.source>${java.version}</maven.compiler.source>
@@ -37,7 +37,7 @@ under the License.
 	<dependencies>
 		<dependency>
 			<groupId>org.apache.flink</groupId>
-			<artifactId>flink-streaming-java_${scala.binary.version}</artifactId>
+			<artifactId>flink-streaming-java</artifactId>
 			<version>${flink.version}</version>
 			<scope>provided</scope>
 		</dependency>
diff --git a/testing/docker-test-job/src/main/java/org/apache/flink/StreamingJob.java b/testing/docker-test-job/src/main/java/org/apache/flink/StreamingJob.java
index 4806a438..ee67a652 100644
--- a/testing/docker-test-job/src/main/java/org/apache/flink/StreamingJob.java
+++ b/testing/docker-test-job/src/main/java/org/apache/flink/StreamingJob.java
@@ -18,31 +18,184 @@
 
 package org.apache.flink;
 
+import org.apache.flink.api.common.eventtime.WatermarkStrategy;
+import org.apache.flink.api.connector.source.Boundedness;
+import org.apache.flink.api.connector.source.ReaderOutput;
+import org.apache.flink.api.connector.source.Source;
+import org.apache.flink.api.connector.source.SourceReader;
+import org.apache.flink.api.connector.source.SourceReaderContext;
+import org.apache.flink.api.connector.source.SourceSplit;
+import org.apache.flink.api.connector.source.SplitEnumerator;
+import org.apache.flink.api.connector.source.SplitEnumeratorContext;
+import org.apache.flink.core.io.InputStatus;
+import org.apache.flink.core.io.SimpleVersionedSerializer;
 import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
-import org.apache.flink.streaming.api.functions.source.SourceFunction;
+
+import javax.annotation.Nullable;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
 
 public class StreamingJob {
 
 	public static void main(String[] args) throws Exception {
 		final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
-		env.addSource(new InfiniteSource()).map(x -> x);
+		env.fromSource(new InfiniteSource(), WatermarkStrategy.noWatermarks(), "source")
+				.map(x -> x);
 		env.execute();
 	}
 
-	private static final class InfiniteSource implements SourceFunction<Integer> {
+	/** Infinite source for testing. */
+	private static final class InfiniteSource
+			implements Source<Integer, DummySplit, NoOpEnumState> {
+		@Override
+		public Boundedness getBoundedness() {
+			return Boundedness.CONTINUOUS_UNBOUNDED;
+		}
+
+		@Override
+		public SplitEnumerator<DummySplit, NoOpEnumState> createEnumerator(
+				SplitEnumeratorContext<DummySplit> splitEnumeratorContext) throws Exception {
+			return new NoOpEnumerator();
+		}
+
+		@Override
+		public SplitEnumerator<DummySplit, NoOpEnumState> restoreEnumerator(
+				SplitEnumeratorContext<DummySplit> splitEnumeratorContext,
+				NoOpEnumState noOpEnumState)
+				throws Exception {
+			return new NoOpEnumerator();
+		}
+
+		@Override
+		public SimpleVersionedSerializer<DummySplit> getSplitSerializer() {
+			return new DummySplitSerializer();
+		}
+
+		@Override
+		public SimpleVersionedSerializer<NoOpEnumState> getEnumeratorCheckpointSerializer() {
+			return new NoOpEnumStateSerializer();
+		}
+
+		@Override
+		public SourceReader<Integer, DummySplit> createReader(
+				SourceReaderContext sourceReaderContext) throws Exception {
+			return new InfiniteSourceReader();
+		}
+	}
+
+	/** Reader for {@link InfiniteSource}. */
+	private static class InfiniteSourceReader implements SourceReader<Integer, DummySplit> {
+
+		@Override
+		public InputStatus pollNext(ReaderOutput<Integer> readerOutput) throws Exception {
+			Thread.sleep(20);
+			return InputStatus.MORE_AVAILABLE;
+		}
+
+		@Override
+		public List<DummySplit> snapshotState(long l) {
+			return Collections.singletonList(new DummySplit());
+		}
+
+		@Override
+		public CompletableFuture<Void> isAvailable() {
+			return CompletableFuture.completedFuture(null);
+		}
+
+		@Override
+		public void start() {
+			// no op
+		}
+
+		@Override
+		public void addSplits(List<DummySplit> list) {
+			// no op
+		}
+
+		@Override
+		public void notifyNoMoreSplits() {
+			// no op
+		}
+
+		@Override
+		public void close() throws Exception {
+			// no op
+		}
+	}
+
+	/** Mock enumerator. */
+	private static class NoOpEnumerator implements SplitEnumerator<DummySplit, NoOpEnumState> {
+		@Override
+		public void start() {}
+
+		@Override
+		public void handleSplitRequest(int subtaskId, @Nullable String requesterHostname) {}
+
+		@Override
+		public void addSplitsBack(List<DummySplit> splits, int subtaskId) {}
+
+		@Override
+		public void addReader(int subtaskId) {}
+
+		@Override
+		public NoOpEnumState snapshotState(long checkpointId) throws Exception {
+			return new NoOpEnumState();
+		}
+
+		@Override
+		public void close() throws IOException {}
+	}
+
+	/** The split of the {@link InfiniteSource}. */
+	private static class DummySplit implements SourceSplit {
+		public static final String SPLIT_ID = "DummySplitId";
+
+		@Override
+		public String splitId() {
+			return SPLIT_ID;
+		}
+	}
+
+	/** Dummy enum state. */
+	private static class NoOpEnumState {}
 
-		private volatile boolean running = true;
+	/** Mock enumerator state serializer. */
+	private static class NoOpEnumStateSerializer
+			implements SimpleVersionedSerializer<NoOpEnumState> {
+		@Override
+		public int getVersion() {
+			return 0;
+		}
+
+		@Override
+		public byte[] serialize(NoOpEnumState obj) throws IOException {
+			return new byte[0];
+		}
+
+		@Override
+		public NoOpEnumState deserialize(int version, byte[] serialized) throws IOException {
+			return new NoOpEnumState();
+		}
+	}
+
+	private static class DummySplitSerializer implements SimpleVersionedSerializer<DummySplit> {
+
+		@Override
+		public int getVersion() {
+			return 0;
+		}
 
 		@Override
-		public void run(SourceContext<Integer> ctx) throws Exception {
-			while (running) {
-				Thread.sleep(20);
-			}
+		public byte[] serialize(DummySplit obj) throws IOException {
+			return new byte[0];
 		}
 
 		@Override
-		public void cancel() {
-			running = false;
+		public DummySplit deserialize(int version, byte[] serialized) throws IOException {
+			return new DummySplit();
 		}
 	}
-}
+}
\ No newline at end of file