diff --git a/org.jacoco.core.test/src/org/jacoco/core/analysis/AnalyzerTest.java b/org.jacoco.core.test/src/org/jacoco/core/analysis/AnalyzerTest.java
index 0e979f6ce9..f2a79515cb 100644
--- a/org.jacoco.core.test/src/org/jacoco/core/analysis/AnalyzerTest.java
+++ b/org.jacoco.core.test/src/org/jacoco/core/analysis/AnalyzerTest.java
@@ -125,6 +125,23 @@ private static byte[] createClass(final int version) {
 		return cw.toByteArray();
 	}
 
+	/**
+	 * @see #analyzeAll_should_throw_exception_for_unsupported_class_file_version()
+	 */
+	@Test
+	public void analyzeClass_should_throw_exception_for_unsupported_class_file_version() {
+		final byte[] bytes = createClass(Opcodes.V14 + 1);
+		try {
+			analyzer.analyzeClass(bytes, "UnsupportedVersion");
+			fail("exception expected");
+		} catch (IOException e) {
+			assertEquals("Error while analyzing UnsupportedVersion.",
+					e.getMessage());
+			assertEquals("Unsupported class file major version 59",
+					e.getCause().getMessage());
+		}
+	}
+
 	@Test
 	public void testAnalyzeClassFromStream() throws IOException {
 		analyzer.analyzeClass(TargetLoader.getClassData(AnalyzerTest.class),
@@ -196,6 +213,24 @@ public void testAnalyzeClass_BrokenStream() throws IOException {
 		}
 	}
 
+	/**
+	 * @see #analyzeClass_should_throw_exception_for_unsupported_class_file_version()
+	 */
+	@Test
+	public void analyzeAll_should_throw_exception_for_unsupported_class_file_version() {
+		final byte[] bytes = createClass(Opcodes.V14 + 1);
+		try {
+			analyzer.analyzeAll(new ByteArrayInputStream(bytes),
+					"UnsupportedVersion");
+			fail("exception expected");
+		} catch (IOException e) {
+			assertEquals("Error while analyzing UnsupportedVersion.",
+					e.getMessage());
+			assertEquals("Unsupported class file major version 59",
+					e.getCause().getMessage());
+		}
+	}
+
 	@Test
 	public void testAnalyzeAll_Class() throws IOException {
 		final int count = analyzer.analyzeAll(
diff --git a/org.jacoco.core.test/src/org/jacoco/core/instr/InstrumenterTest.java b/org.jacoco.core.test/src/org/jacoco/core/instr/InstrumenterTest.java
index 79f11c6c02..0fa42ecd5c 100644
--- a/org.jacoco.core.test/src/org/jacoco/core/instr/InstrumenterTest.java
+++ b/org.jacoco.core.test/src/org/jacoco/core/instr/InstrumenterTest.java
@@ -117,6 +117,23 @@ private static byte[] createClass(final int version) {
 		return cw.toByteArray();
 	}
 
+	/**
+	 * @see #instrumentAll_should_throw_exception_for_unsupported_class_file_version()
+	 */
+	@Test
+	public void instrument_should_throw_exception_for_unsupported_class_file_version() {
+		final byte[] bytes = createClass(Opcodes.V14 + 1);
+		try {
+			instrumenter.instrument(bytes, "UnsupportedVersion");
+			fail("exception expected");
+		} catch (final IOException e) {
+			assertEquals("Error while instrumenting UnsupportedVersion.",
+					e.getMessage());
+			assertEquals("Unsupported class file major version 59",
+					e.getCause().getMessage());
+		}
+	}
+
 	@Test
 	public void testInstrumentClass() throws Exception {
 		byte[] bytes = instrumenter.instrument(
@@ -202,6 +219,24 @@ public void testSerialization() throws Exception {
 		assertEquals("Hello42", obj2.toString());
 	}
 
+	/**
+	 * @see #instrument_should_throw_exception_for_unsupported_class_file_version()
+	 */
+	@Test
+	public void instrumentAll_should_throw_exception_for_unsupported_class_file_version() {
+		final byte[] bytes = createClass(Opcodes.V14 + 1);
+		try {
+			instrumenter.instrumentAll(new ByteArrayInputStream(bytes),
+					new ByteArrayOutputStream(), "UnsupportedVersion");
+			fail("exception expected");
+		} catch (final IOException e) {
+			assertEquals("Error while instrumenting UnsupportedVersion.",
+					e.getMessage());
+			assertEquals("Unsupported class file major version 59",
+					e.getCause().getMessage());
+		}
+	}
+
 	@Test
 	public void testInstrumentAll_Class() throws IOException {
 		InputStream in = TargetLoader.getClassData(getClass());
diff --git a/org.jacoco.core.test/src/org/jacoco/core/internal/ContentTypeDetectorTest.java b/org.jacoco.core.test/src/org/jacoco/core/internal/ContentTypeDetectorTest.java
index d96c6683b8..a35c0e657f 100644
--- a/org.jacoco.core.test/src/org/jacoco/core/internal/ContentTypeDetectorTest.java
+++ b/org.jacoco.core.test/src/org/jacoco/core/internal/ContentTypeDetectorTest.java
@@ -180,6 +180,21 @@ public void should_detect_java_14_with_preview_features() throws IOException {
 		assertContent();
 	}
 
+	@Test
+	public void should_detect_java_42() throws IOException {
+		initData(0xCA, 0xFE, 0xBA, 0xBE, 0x00, 0x00, 0x00, 0x56);
+		assertEquals(ContentTypeDetector.CLASSFILE, detector.getType());
+		assertContent();
+	}
+
+	@Test
+	public void should_not_detect_MachO_fat_binary_with_44_architectures()
+			throws IOException {
+		initData(0xCA, 0xFE, 0xBA, 0xBE, 0x00, 0x00, 0x00, 0x2C);
+		assertEquals(ContentTypeDetector.UNKNOWN, detector.getType());
+		assertContent();
+	}
+
 	@Test
 	public void testMachObjectFile() throws IOException {
 		initData(0xCA, 0xFE, 0xBA, 0xBE, 0x00, 0x00, 0x00, 0x02);
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java b/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
index 9bf8ec2f6c..eefb9ef006 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
@@ -16,8 +16,6 @@
 import java.io.IOException;
 import java.io.InputStream;
 
-import org.objectweb.asm.Opcodes;
-
 /**
  * Detector for content types of binary streams based on a magic headers.
  */
@@ -73,26 +71,14 @@ private static int determineType(final InputStream in) throws IOException {
 		case PACK200FILE:
 			return PACK200FILE;
 		case CLASSFILE:
-			// also verify version to distinguish from Mach Object files:
-			switch (readInt(in)) {
-			case Opcodes.V1_1:
-			case Opcodes.V1_2:
-			case Opcodes.V1_3:
-			case Opcodes.V1_4:
-			case Opcodes.V1_5:
-			case Opcodes.V1_6:
-			case Opcodes.V1_7:
-			case Opcodes.V1_8:
-			case Opcodes.V9:
-			case Opcodes.V10:
-			case Opcodes.V11:
-			case Opcodes.V11 | Opcodes.V_PREVIEW:
-			case Opcodes.V12:
-			case Opcodes.V12 | Opcodes.V_PREVIEW:
-			case Opcodes.V13:
-			case Opcodes.V13 | Opcodes.V_PREVIEW:
-			case (Opcodes.V13 + 1):
-			case (Opcodes.V13 + 1) | Opcodes.V_PREVIEW:
+			// Mach-O fat/universal binaries have the same magic header as Java
+			// class files, number of architectures is stored in unsigned 4
+			// bytes in the same place and in the same big-endian order as major
+			// and minor version of class file. Hopefully on practice number of
+			// architectures in single executable is less than 45, which is
+			// major version of Java 1.1 class files:
+			final int majorVersion = readInt(in) & 0xFFFF;
+			if (majorVersion >= 45) {
 				return CLASSFILE;
 			}
 		}
diff --git a/org.jacoco.doc/docroot/doc/changes.html b/org.jacoco.doc/docroot/doc/changes.html
index 174ebe3e6e..ac3e861564 100644
--- a/org.jacoco.doc/docroot/doc/changes.html
+++ b/org.jacoco.doc/docroot/doc/changes.html
@@ -70,6 +70,10 @@ <h3>API Changes</h3>
         a coverage ratio limit is configured outside the range [0,1] to avoid
         common configuration mistakes
         (GitHub <a href="https://github.com/jacoco/jacoco/issues/783">#783</a>).</li>
+  <li>Unsupported class file versions are now consistently reported as exceptions
+      by all methods of <code>Analyzer</code> and <code>Instrumenter</code> and
+      thus also during report generation and offline instrumentation
+      (GitHub <a href="https://github.com/jacoco/jacoco/issues/952">#952</a>).</li>
 </ul>
 
 <h2>Release 0.8.4 (2019/05/08)</h2>