diff --git a/php/utils.php b/php/utils.php
index 6daaeb171..939b6c1f1 100644
--- a/php/utils.php
+++ b/php/utils.php
@@ -962,12 +962,16 @@ function get_named_sem_ver( $new_version, $original_version ) {
 		$patch = $bits[2];
 	}
 
-	if ( isset( $minor ) && Semver::satisfies( $new_version, "{$major}.{$minor}.x" ) ) {
-		return 'patch';
-	}
+	try {
+		if ( isset( $minor ) && Semver::satisfies( $new_version, "{$major}.{$minor}.x" ) ) {
+			return 'patch';
+		}
 
-	if ( Semver::satisfies( $new_version, "{$major}.x.x" ) ) {
-		return 'minor';
+		if ( Semver::satisfies( $new_version, "{$major}.x.x" ) ) {
+			return 'minor';
+		}
+	} catch ( \UnexpectedValueException $e ) {
+		return '';
 	}
 
 	return 'major';
diff --git a/tests/test-utils.php b/tests/test-utils.php
index 3e43256e6..2bf02fbb1 100644
--- a/tests/test-utils.php
+++ b/tests/test-utils.php
@@ -43,6 +43,12 @@ public function testGetSemVer() {
 		$original_version = '0.19.1';
 		$this->assertEmpty( Utils\get_named_sem_ver( '0.18.0', $original_version ) );
 		$this->assertEmpty( Utils\get_named_sem_ver( '0.19.1', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( 'nonsense', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '0.18.1-beta3', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '0.19.1-dev1', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '0.19.1-beta3', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '0.19.2-dev1', $original_version ) ); // -dev suffix not accepted by SemVer.
+		$this->assertEquals( 'patch', Utils\get_named_sem_ver( '0.19.2-beta3', $original_version ) );
 		$this->assertEquals( 'patch', Utils\get_named_sem_ver( '0.19.2', $original_version ) );
 		$this->assertEquals( 'minor', Utils\get_named_sem_ver( '0.20.0', $original_version ) );
 		$this->assertEquals( 'minor', Utils\get_named_sem_ver( '0.20.3', $original_version ) );
@@ -54,7 +60,14 @@ public function testGetSemVerWP() {
 		$original_version = '3.0';
 		$this->assertEmpty( Utils\get_named_sem_ver( '2.8', $original_version ) );
 		$this->assertEmpty( Utils\get_named_sem_ver( '2.9.1', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( 'nonsense', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '2.0-beta3', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '3.0-dev1', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '3.0-beta3', $original_version ) );
+		$this->assertEmpty( Utils\get_named_sem_ver( '3.0.1-dev1', $original_version ) ); // -dev suffix not accepted by SemVer.
+		$this->assertEquals( 'patch', Utils\get_named_sem_ver( '3.0.1-beta3', $original_version ) );
 		$this->assertEquals( 'patch', Utils\get_named_sem_ver( '3.0.1', $original_version ) );
+		$this->assertEquals( 'minor', Utils\get_named_sem_ver( '3.1-beta3', $original_version ) );
 		$this->assertEquals( 'minor', Utils\get_named_sem_ver( '3.1', $original_version ) );
 		$this->assertEquals( 'minor', Utils\get_named_sem_ver( '3.1.1', $original_version ) );
 		$this->assertEquals( 'major', Utils\get_named_sem_ver( '4.0', $original_version ) );