diff --git a/src/main/java/org/gitlab4j/api/systemhooks/AbstractSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/AbstractSystemHookEvent.java
index 0fc188aed..6d30d4696 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/AbstractSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/AbstractSystemHookEvent.java
@@ -3,6 +3,7 @@
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 public abstract class AbstractSystemHookEvent implements SystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     private String requestUrl;
     private String requestQueryString;
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/GroupMemberSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/GroupMemberSystemHookEvent.java
index afb89870b..92c7b7f53 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/GroupMemberSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/GroupMemberSystemHookEvent.java
@@ -5,6 +5,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class GroupMemberSystemHookEvent extends AbstractSystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String NEW_GROUP_MEMBER_EVENT = "user_add_to_group";
     public static final String GROUP_MEMBER_REMOVED_EVENT = "user_remove_from_group";
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/GroupSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/GroupSystemHookEvent.java
index 76f9f7138..e39749283 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/GroupSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/GroupSystemHookEvent.java
@@ -5,6 +5,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class GroupSystemHookEvent extends AbstractSystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String GROUP_CREATE_EVENT = "group_create";
     public static final String GROUP_DESTROY_EVENT = "group_destroy";
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/KeySystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/KeySystemHookEvent.java
index ed29138a7..209affea7 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/KeySystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/KeySystemHookEvent.java
@@ -5,7 +5,8 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class KeySystemHookEvent extends AbstractSystemHookEvent {
-    
+    private static final long serialVersionUID = 1L;
+
     public static final String KEY_CREATE_EVENT = "key_create";
     public static final String KEY_DESTROY_EVENT = "key_destroy";
     
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/MergeRequestSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/MergeRequestSystemHookEvent.java
index fdee2a44a..d0f791d28 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/MergeRequestSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/MergeRequestSystemHookEvent.java
@@ -3,6 +3,7 @@
 import org.gitlab4j.api.webhook.MergeRequestEvent;
 
 public class MergeRequestSystemHookEvent extends MergeRequestEvent implements SystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "System Hook";
     public static final String MERGE_REQUEST_EVENT = "merge_request";
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/ProjectSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/ProjectSystemHookEvent.java
index 0ab31ad7b..7dea5a22b 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/ProjectSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/ProjectSystemHookEvent.java
@@ -6,6 +6,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class ProjectSystemHookEvent extends AbstractSystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String PROJECT_CREATE_EVENT = "project_create";
     public static final String PROJECT_DESTROY_EVENT = "project_destroy";
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/PushSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/PushSystemHookEvent.java
index 95d1bc8fc..bff70bffe 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/PushSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/PushSystemHookEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.webhook.AbstractPushEvent;
 
 public class PushSystemHookEvent extends AbstractPushEvent implements SystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String PUSH_EVENT = "push";
 
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/SystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/SystemHookEvent.java
index daaab704f..1d6a52e6a 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/SystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/SystemHookEvent.java
@@ -1,5 +1,7 @@
 package org.gitlab4j.api.systemhooks;
 
+import java.io.Serializable;
+
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
@@ -31,7 +33,7 @@
     @JsonSubTypes.Type(value = RepositorySystemHookEvent.class, name = RepositorySystemHookEvent.REPOSITORY_UPDATE_EVENT),
     @JsonSubTypes.Type(value = MergeRequestSystemHookEvent.class, name = MergeRequestSystemHookEvent.MERGE_REQUEST_EVENT)
 })
-public interface SystemHookEvent {
+public interface SystemHookEvent extends Serializable {
 
     String getEventName();
 
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/TagPushSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/TagPushSystemHookEvent.java
index 7833bb7ea..021bd12ba 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/TagPushSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/TagPushSystemHookEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.webhook.AbstractPushEvent;
 
 public class TagPushSystemHookEvent extends AbstractPushEvent implements SystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String TAG_PUSH_EVENT = "tag_push";
 
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/TeamMemberSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/TeamMemberSystemHookEvent.java
index 7c844506b..f8b31851d 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/TeamMemberSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/TeamMemberSystemHookEvent.java
@@ -6,6 +6,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class TeamMemberSystemHookEvent extends AbstractSystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String NEW_TEAM_MEMBER_EVENT = "user_add_to_team";
     public static final String TEAM_MEMBER_REMOVED_EVENT = "user_remove_from_team";
diff --git a/src/main/java/org/gitlab4j/api/systemhooks/UserSystemHookEvent.java b/src/main/java/org/gitlab4j/api/systemhooks/UserSystemHookEvent.java
index 09e1775a1..518c6db69 100644
--- a/src/main/java/org/gitlab4j/api/systemhooks/UserSystemHookEvent.java
+++ b/src/main/java/org/gitlab4j/api/systemhooks/UserSystemHookEvent.java
@@ -5,6 +5,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class UserSystemHookEvent extends AbstractSystemHookEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String USER_CREATE_EVENT = "user_create";
     public static final String USER_DESTROY_EVENT = "user_destroy";
diff --git a/src/main/java/org/gitlab4j/api/webhook/AbstractEvent.java b/src/main/java/org/gitlab4j/api/webhook/AbstractEvent.java
index b32be6f58..1a27df340 100644
--- a/src/main/java/org/gitlab4j/api/webhook/AbstractEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/AbstractEvent.java
@@ -3,8 +3,9 @@
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 public abstract class AbstractEvent implements Event {
+    private static final long serialVersionUID = 1L;
 
-    private String requestUrl;
+	private String requestUrl;
     private String requestQueryString;
     private String secretToken;
 
diff --git a/src/main/java/org/gitlab4j/api/webhook/BuildEvent.java b/src/main/java/org/gitlab4j/api/webhook/BuildEvent.java
index 08938b689..884e51f82 100644
--- a/src/main/java/org/gitlab4j/api/webhook/BuildEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/BuildEvent.java
@@ -12,6 +12,7 @@
  * Job Events</a> is incorrect, this class represents the actual content of the Job Hook event.
  */
 public class BuildEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String JOB_HOOK_X_GITLAB_EVENT = "Job Hook";
     public static final String OBJECT_KIND = "build";
diff --git a/src/main/java/org/gitlab4j/api/webhook/DeploymentEvent.java b/src/main/java/org/gitlab4j/api/webhook/DeploymentEvent.java
index 8491fca63..8fc9af407 100644
--- a/src/main/java/org/gitlab4j/api/webhook/DeploymentEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/DeploymentEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class DeploymentEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Deployment Hook";
     public static final String OBJECT_KIND = "deployment";
diff --git a/src/main/java/org/gitlab4j/api/webhook/Event.java b/src/main/java/org/gitlab4j/api/webhook/Event.java
index e95090cec..e4387f4de 100644
--- a/src/main/java/org/gitlab4j/api/webhook/Event.java
+++ b/src/main/java/org/gitlab4j/api/webhook/Event.java
@@ -1,5 +1,7 @@
 package org.gitlab4j.api.webhook;
 
+import java.io.Serializable;
+
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
@@ -21,7 +23,7 @@
     @JsonSubTypes.Type(value = DeploymentEvent.class, name = DeploymentEvent.OBJECT_KIND),
     @JsonSubTypes.Type(value = ReleaseEvent.class, name = ReleaseEvent.OBJECT_KIND)
 })
-public interface Event {     
+public interface Event extends Serializable {
     String getObjectKind();
 
     void setRequestUrl(String url);
diff --git a/src/main/java/org/gitlab4j/api/webhook/IssueEvent.java b/src/main/java/org/gitlab4j/api/webhook/IssueEvent.java
index a5b38d1ea..cfa31ec3c 100644
--- a/src/main/java/org/gitlab4j/api/webhook/IssueEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/IssueEvent.java
@@ -7,6 +7,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class IssueEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Issue Hook";
     public static final String OBJECT_KIND = "issue";
diff --git a/src/main/java/org/gitlab4j/api/webhook/JobEvent.java b/src/main/java/org/gitlab4j/api/webhook/JobEvent.java
index 072df924f..208971a1b 100644
--- a/src/main/java/org/gitlab4j/api/webhook/JobEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/JobEvent.java
@@ -8,6 +8,7 @@
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 public class JobEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String JOB_HOOK_X_GITLAB_EVENT = "Job Hook";
     public static final String OBJECT_KIND = "job";
diff --git a/src/main/java/org/gitlab4j/api/webhook/MergeRequestEvent.java b/src/main/java/org/gitlab4j/api/webhook/MergeRequestEvent.java
index 48592e682..c7a707d41 100644
--- a/src/main/java/org/gitlab4j/api/webhook/MergeRequestEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/MergeRequestEvent.java
@@ -8,6 +8,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class MergeRequestEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Merge Request Hook";
     public static final String OBJECT_KIND = "merge_request";
diff --git a/src/main/java/org/gitlab4j/api/webhook/NoteEvent.java b/src/main/java/org/gitlab4j/api/webhook/NoteEvent.java
index b22c762ec..afbe51915 100644
--- a/src/main/java/org/gitlab4j/api/webhook/NoteEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/NoteEvent.java
@@ -11,6 +11,7 @@
 import com.fasterxml.jackson.annotation.JsonValue;
 
 public class NoteEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Note Hook";
     public static final String OBJECT_KIND = "note";
diff --git a/src/main/java/org/gitlab4j/api/webhook/PipelineEvent.java b/src/main/java/org/gitlab4j/api/webhook/PipelineEvent.java
index 1e819100e..f04723f8b 100644
--- a/src/main/java/org/gitlab4j/api/webhook/PipelineEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/PipelineEvent.java
@@ -9,6 +9,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class PipelineEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Pipeline Hook";
     public static final String OBJECT_KIND = "pipeline";
diff --git a/src/main/java/org/gitlab4j/api/webhook/PushEvent.java b/src/main/java/org/gitlab4j/api/webhook/PushEvent.java
index c81f19b64..ce5f75983 100644
--- a/src/main/java/org/gitlab4j/api/webhook/PushEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/PushEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class PushEvent extends AbstractPushEvent implements Event {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Push Hook";
     public static final String OBJECT_KIND = "push";
diff --git a/src/main/java/org/gitlab4j/api/webhook/ReleaseEvent.java b/src/main/java/org/gitlab4j/api/webhook/ReleaseEvent.java
index c89f62359..e32118695 100644
--- a/src/main/java/org/gitlab4j/api/webhook/ReleaseEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/ReleaseEvent.java
@@ -3,6 +3,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class ReleaseEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Release Hook";
     public static final String OBJECT_KIND = "release";
diff --git a/src/main/java/org/gitlab4j/api/webhook/TagPushEvent.java b/src/main/java/org/gitlab4j/api/webhook/TagPushEvent.java
index b4f7f6ab6..0d6d75a02 100644
--- a/src/main/java/org/gitlab4j/api/webhook/TagPushEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/TagPushEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class TagPushEvent extends AbstractPushEvent implements Event {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Tag Push Hook";
     public static final String OBJECT_KIND = "tag_push";
diff --git a/src/main/java/org/gitlab4j/api/webhook/WikiPageEvent.java b/src/main/java/org/gitlab4j/api/webhook/WikiPageEvent.java
index 7980c0529..e8bda72a3 100644
--- a/src/main/java/org/gitlab4j/api/webhook/WikiPageEvent.java
+++ b/src/main/java/org/gitlab4j/api/webhook/WikiPageEvent.java
@@ -4,6 +4,7 @@
 import org.gitlab4j.api.utils.JacksonJson;
 
 public class WikiPageEvent extends AbstractEvent {
+    private static final long serialVersionUID = 1L;
 
     public static final String X_GITLAB_EVENT = "Wiki Page Hook";
     public static final String OBJECT_KIND = "wiki_page";