diff --git a/pom.xml b/pom.xml
index 4ed4f8a..3c8338d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 
     <groupId>io.digitalstate.stix</groupId>
     <artifactId>stix</artifactId>
-    <version>v0.6</version>
+    <version>v0.6.1</version>
     <packaging>jar</packaging>
 
     <name>STIX 2</name>
@@ -65,7 +65,6 @@
             <version>2.4.0</version>
         </dependency>
 
-
         <dependency>
             <groupId>org.hibernate.validator</groupId>
             <artifactId>hibernate-validator</artifactId>
@@ -125,6 +124,7 @@
             <groupId>org.codehaus.groovy</groupId>
             <artifactId>groovy-all</artifactId>
             <version>2.4.15</version>
+            <scope>test</scope>
         </dependency>
         <dependency> <!-- enables mocking of classes (in addition to interfaces) -->
             <groupId>net.bytebuddy</groupId>
@@ -174,7 +174,7 @@
                 <executions>
                     <execution>
                         <goals>
-                            <goal>compile</goal>
+                            <!--<goal>compile</goal>-->
                             <goal>compileTests</goal>
                         </goals>
                     </execution>
diff --git a/src/main/java/io/digitalstate/stix/common/StixModified.java b/src/main/java/io/digitalstate/stix/common/StixModified.java
index e8e0c85..fabdb3f 100644
--- a/src/main/java/io/digitalstate/stix/common/StixModified.java
+++ b/src/main/java/io/digitalstate/stix/common/StixModified.java
@@ -19,7 +19,7 @@ public interface StixModified {
     @NotNull
     @JsonProperty("modified")
     @JsonPropertyDescription("The modified property represents the time that this particular version of the object was created. The timstamp value MUST be precise to the nearest millisecond.")
-   @JsonFormat(pattern = StixDataFormats.TIMESTAMP_PATTERN, timezone = "UTC")
+    @JsonFormat(pattern = StixDataFormats.TIMESTAMP_PATTERN, timezone = "UTC")
     @Value.Default
     @Redactable
     default Instant getModified(){
diff --git a/src/main/java/io/digitalstate/stix/coo/objects/ProcessCoo.java b/src/main/java/io/digitalstate/stix/coo/objects/ProcessCoo.java
index 7582aee..d07f49c 100644
--- a/src/main/java/io/digitalstate/stix/coo/objects/ProcessCoo.java
+++ b/src/main/java/io/digitalstate/stix/coo/objects/ProcessCoo.java
@@ -4,6 +4,7 @@
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import io.digitalstate.stix.coo.CyberObservableObject;
+import io.digitalstate.stix.helpers.StixDataFormats;
 import io.digitalstate.stix.validation.contraints.businessrule.BusinessRule;
 import io.digitalstate.stix.validation.contraints.defaulttypevalue.DefaultTypeValue;
 import io.digitalstate.stix.validation.groups.DefaultValuesProcessor;
@@ -35,7 +36,7 @@
 @JsonPropertyOrder({ "type", "extensions", "is_hidden", "pid", "name", "created", "cwd", "arguments", "command_line",
         "environment_variables", "opened_connection_refs", "creator_user_ref", "binary_ref", "parent_ref",
         "child_refs" })
-@BusinessRule(ifExp = "true", thenExp = "getExtensions().isEmpty() == false || isHidden().isPresent() == true || getPid().isPresent() == true || getName().isPresent() == true || getCreated().isPresent() == true || getCwd().isPresent() == true || getArguments().isEmpty() == false || getCommandLine().isPresent() == true || getEnvironmentVariables().isEmpty() == false || getOpenedConnectionRefs().isEmpty() == false || getCreatorUserRef().isPresent() == true || getBinaryRef().isPresent() == true || getParentRef().isPresent() == true || getChildRefs().isEmpty == false", errorMessage = "A Process Object MUST contain at least one property (other than type) from this object (or one of its extensions).")
+@BusinessRule(ifExp = "true", thenExp = "getExtensions().isEmpty() == false || isHidden().isPresent() == true || getPid().isPresent() == true || getName().isPresent() == true || getCreated().isPresent() == true || getCwd().isPresent() == true || getArguments().isEmpty() == false || getCommandLine().isPresent() == true || getEnvironmentVariables().isEmpty() == false || getOpenedConnectionRefs().isEmpty() == false || getCreatorUserRef().isPresent() == true || getBinaryRef().isPresent() == true || getParentRef().isPresent() == true || getChildRefs().isEmpty() == false", errorMessage = "A Process Object MUST contain at least one property (other than type) from this object (or one of its extensions).")
 public interface ProcessCoo extends CyberObservableObject {
 
     @JsonProperty("is_hidden")
@@ -53,6 +54,7 @@ public interface ProcessCoo extends CyberObservableObject {
 
     @JsonProperty("created")
     @JsonPropertyDescription("Specifies the date/time at which the process was created.")
+    @JsonFormat(shape=JsonFormat.Shape.STRING, pattern = StixDataFormats.TIMESTAMP_PATTERN, timezone = "UTC")
     Optional<Instant> getCreated();
 
     @JsonProperty("cwd")
diff --git a/src/test/groovy/stix/sdo/ObservedDataSpec.groovy b/src/test/groovy/stix/sdo/ObservedDataSpec.groovy
index 005ea4a..f403295 100644
--- a/src/test/groovy/stix/sdo/ObservedDataSpec.groovy
+++ b/src/test/groovy/stix/sdo/ObservedDataSpec.groovy
@@ -43,6 +43,6 @@ class ObservedDataSpec extends Specification implements StixMockDataGenerator {
             JSONAssert.assertEquals(originalJsonString, newJsonString, JSONCompareMode.NON_EXTENSIBLE)
 
         where:
-            i << (1..1000) // More tests are run because of the large variation of probabilities and number of combinations
+            i << (1..5000) // More tests are run because of the large variation of probabilities and number of combinations
     }
 }
diff --git a/src/test/groovy/stix/sdo/ReportSpec.groovy b/src/test/groovy/stix/sdo/ReportSpec.groovy
index b0abd6b..4d4c907 100644
--- a/src/test/groovy/stix/sdo/ReportSpec.groovy
+++ b/src/test/groovy/stix/sdo/ReportSpec.groovy
@@ -43,6 +43,6 @@ class ReportSpec extends Specification implements StixMockDataGenerator {
             JSONAssert.assertEquals(originalJsonString, newJsonString, JSONCompareMode.NON_EXTENSIBLE)
 
         where:
-            i << (1..100) // More tests are run because of the large variation of probabilities and number of combinations
+            i << (1..500) // More tests are run because of the large variation of probabilities and number of combinations
     }
 }