diff --git a/examples/pom.xml b/examples/pom.xml
index 42abdba..9d87c9e 100644
--- a/examples/pom.xml
+++ b/examples/pom.xml
@@ -5,7 +5,7 @@
   <parent>
     <groupId>com.opengamma</groupId>
     <artifactId>corporate-parent</artifactId>
-    <version>2.8.1</version>
+    <version>3.0.3</version>
     <relativePath />
   </parent>
   <groupId>com.opengamma.sdk</groupId>
@@ -66,6 +66,10 @@
 
   <!-- ==================================================================== -->
   <properties>
+    <!-- corporate-parent 3.0.3 defaults to Java 21; this SDK must stay on Java 8 -->
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <maven.compiler.release>8</maven.compiler.release>
     <!-- Version -->
     <logback-classic.version>1.2.13</logback-classic.version>
     <!-- Properties for joda-beans-maven-plugin -->
diff --git a/modules/margin/src/test/java/com/opengamma/sdk/margin/PortfolioDataFileTest.java b/modules/margin/src/test/java/com/opengamma/sdk/margin/PortfolioDataFileTest.java
index 4787c95..b20d257 100644
--- a/modules/margin/src/test/java/com/opengamma/sdk/margin/PortfolioDataFileTest.java
+++ b/modules/margin/src/test/java/com/opengamma/sdk/margin/PortfolioDataFileTest.java
@@ -7,6 +7,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -15,9 +16,12 @@
 import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.Base64;
+import java.util.LinkedHashMap;
+import java.util.Map;
 import java.util.Random;
 import java.util.zip.GZIPOutputStream;
 import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
 import java.util.zip.ZipOutputStream;
 
 import org.joda.beans.Bean;
@@ -34,7 +38,7 @@ public class PortfolioDataFileTest {
   public void test_ofString_small() {
     PortfolioDataFile test = PortfolioDataFile.of("name.txt", "a=b");
     assertThat(test.getName()).isEqualTo("name.txt.gz.base64");
-    assertThat(test.getData()).isEqualTo("H4sIAAAAAAAAAEu0TQIAzzAAfwMAAAA=");
+    assertThat(test.getData()).isEqualTo(Base64.getEncoder().encodeToString(gzip("a=b")));
   }
 
   @Test
@@ -101,12 +105,30 @@ public void test_ofBean_trade() {
 
   //-------------------------------------------------------------------------
   @Test
-  public void test_ofCombined() {
+  public void test_ofCombined() throws IOException {
     Path path1 = Paths.get("src/test/resources/simple.xml");
     Path path2 = Paths.get("src/test/resources/simple.xls");
     PortfolioDataFile test = PortfolioDataFile.ofCombined(Arrays.asList(path1, path2));
     assertThat(test.getName()).isEqualTo("JavaSDK.zip.base64");
-    assertThat(test.getData()).isEqualTo(Base64.getEncoder().encodeToString(zip(path1, path2)));
+    byte[] actualZipBytes = Base64.getDecoder().decode(test.getData());
+    assertThat(unzipEntries(actualZipBytes)).isEqualTo(unzipEntries(zip(path1, path2)));
+  }
+
+  private static Map<String, String> unzipEntries(byte[] zipBytes) throws IOException {
+    Map<String, String> entries = new LinkedHashMap<>();
+    try (ZipInputStream zis = new ZipInputStream(new ByteArrayInputStream(zipBytes))) {
+      ZipEntry entry;
+      while ((entry = zis.getNextEntry()) != null) {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        byte[] buf = new byte[4096];
+        int len;
+        while ((len = zis.read(buf)) != -1) {
+          baos.write(buf, 0, len);
+        }
+        entries.put(entry.getName(), Base64.getEncoder().encodeToString(baos.toByteArray()));
+      }
+    }
+    return entries;
   }
 
   private static byte[] gzip(String str) {
diff --git a/modules/pom.xml b/modules/pom.xml
index ecc7f78..3f561fe 100644
--- a/modules/pom.xml
+++ b/modules/pom.xml
@@ -5,7 +5,7 @@
   <parent>
     <groupId>com.opengamma</groupId>
     <artifactId>corporate-parent</artifactId>
-    <version>2.8.1</version>
+    <version>3.0.3</version>
     <relativePath />
   </parent>
   <groupId>com.opengamma.sdk</groupId>
@@ -411,6 +411,10 @@
 
   <!-- ==================================================================== -->
   <properties>
+    <!-- corporate-parent 3.0.3 defaults to Java 21; this SDK must stay on Java 8 -->
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <maven.compiler.release>8</maven.compiler.release>
     <!-- Versions -->
     <assertj.version>3.25.3</assertj.version>
     <jcommander.version>1.82</jcommander.version>