diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/User2UserDtoMapper.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/User2UserDtoMapper.java
index c2bce60820..b7ac65b07f 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/User2UserDtoMapper.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/User2UserDtoMapper.java
@@ -10,6 +10,7 @@ import javax.ws.rs.core.UriInfo;
 import java.time.Instant;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 
 @Mapper
 public abstract class User2UserDtoMapper {
@@ -35,8 +36,16 @@ public abstract class User2UserDtoMapper {
     target.setLinks(links);
   }
 
-  @Mappings({@Mapping(target = "lastModified"), @Mapping(target = "creationDate")})
+  @Mapping(target = "creationDate")
   Instant mapTime(Long epochMilli) {
-    return epochMilli == null? null: Instant.ofEpochMilli(epochMilli);
+    // TODO assert parameter not null
+    return Instant.ofEpochMilli(epochMilli);
+  }
+
+  @Mapping(target = "lastModified")
+  Optional<Instant> mapOptionalTime(Long epochMilli) {
+    return Optional
+      .ofNullable(epochMilli)
+      .map(Instant::ofEpochMilli);
   }
 }
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto.java
index 9bd42d0a87..4e90e0e68f 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto.java
@@ -5,6 +5,7 @@ import lombok.Data;
 import javax.xml.bind.annotation.XmlElement;
 import java.time.Instant;
 import java.util.Map;
+import java.util.Optional;
 
 @Data
 public class UserDto {
@@ -12,7 +13,7 @@ public class UserDto {
   private boolean admin;
   private Instant creationDate;
   private String displayName;
-  private Instant lastModified;
+  private Optional<Instant> lastModified;
   private String mail;
   private String name;
   private String password;
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto2UserMapper.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto2UserMapper.java
index 30b0f16e82..b5573eaa4b 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto2UserMapper.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto2UserMapper.java
@@ -2,10 +2,14 @@ package sonia.scm.api.v2.resources;
 
 import com.google.inject.Inject;
 import org.apache.shiro.authc.credential.PasswordService;
-import org.mapstruct.*;
+import org.mapstruct.Context;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.Named;
 import sonia.scm.user.User;
 
 import java.time.Instant;
+import java.util.Optional;
 
 import static sonia.scm.api.rest.resources.UserResource.DUMMY_PASSWORT;
 
@@ -31,8 +35,14 @@ public abstract class UserDto2UserMapper {
     }
   }
 
-  @Mappings({@Mapping(target = "lastModified"), @Mapping(target = "creationDate")})
+  @Mapping(target = "creationDate")
   Long mapTime(Instant instant) {
-    return instant == null? null: instant.toEpochMilli();
+    // TODO assert parameter not null
+    return instant.toEpochMilli();
+  }
+
+  @Mapping(target = "lastModified")
+  Long mapOptionalTime(Optional<Instant> instant) {
+    return instant.map(Instant::toEpochMilli).orElse(null);
   }
 }
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/User2UserDtoMapperTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/User2UserDtoMapperTest.java
index 63a82520cb..b23dd7db0f 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/User2UserDtoMapperTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/User2UserDtoMapperTest.java
@@ -39,8 +39,7 @@ public class User2UserDtoMapperTest {
 
   @Test
   public void shouldMapLinks_forAdmin() {
-    User user = new User();
-    user.setName("abc");
+    User user = createDefaultUser();
     when(subject.hasRole("admin")).thenReturn(true);
 
     UserDto userDto = mapper.userToUserDto(user, uriInfo);
@@ -51,10 +50,16 @@ public class User2UserDtoMapperTest {
     assertEquals("expected map with create baseUri", expextedBaseUri, userDto.getLinks().get("create").getHref());
   }
 
-  @Test
-  public void shouldMapLinks_forNormalUser() {
+  private User createDefaultUser() {
     User user = new User();
     user.setName("abc");
+    user.setCreationDate(1L);
+    return user;
+  }
+
+  @Test
+  public void shouldMapLinks_forNormalUser() {
+    User user = createDefaultUser();
     when(subject.hasRole("user")).thenReturn(true);
 
     UserDto userDto = mapper.userToUserDto(user, uriInfo);
@@ -67,8 +72,7 @@ public class User2UserDtoMapperTest {
 
   @Test
   public void shouldMapFields() {
-    User user = new User();
-    user.setName("abc");
+    User user = createDefaultUser();
 
     UserDto userDto = mapper.userToUserDto(user, uriInfo);
 
@@ -77,9 +81,8 @@ public class User2UserDtoMapperTest {
 
   @Test
   public void shouldRemovePassword() {
-    User user = new User();
+    User user = createDefaultUser();
     user.setPassword("password");
-    user.setName("abc");
 
     UserDto userDto = mapper.userToUserDto(user, uriInfo);
 
@@ -88,8 +91,7 @@ public class User2UserDtoMapperTest {
 
   @Test
   public void shouldMapTimes() {
-    User user = new User();
-    user.setName("abc");
+    User user = createDefaultUser();
     Instant expectedCreationDate = Instant.ofEpochSecond(6666666);
     Instant expectedModificationDate = expectedCreationDate.plusSeconds(1);
     user.setCreationDate(expectedCreationDate.toEpochMilli());
@@ -98,6 +100,6 @@ public class User2UserDtoMapperTest {
     UserDto userDto = mapper.userToUserDto(user, uriInfo);
 
     assertEquals(expectedCreationDate, userDto.getCreationDate());
-    assertEquals(expectedModificationDate, userDto.getLastModified());
+    assertEquals(expectedModificationDate, userDto.getLastModified().get());
   }
 }
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserDto2UserMapperTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserDto2UserMapperTest.java
index 08b9fe604f..8067846cbd 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserDto2UserMapperTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserDto2UserMapperTest.java
@@ -8,8 +8,10 @@ import org.mockito.Mock;
 import sonia.scm.user.User;
 
 import java.time.Instant;
+import java.util.Optional;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 import static org.mockito.Mockito.when;
 import static org.mockito.MockitoAnnotations.initMocks;
 
@@ -22,8 +24,7 @@ public class UserDto2UserMapperTest {
 
   @Test
   public void shouldMapFields() {
-    UserDto dto = new UserDto();
-    dto.setName("abc");
+    UserDto dto = createDefaultDto();
     User user = mapper.userDtoToUser(dto, "original password");
     assertEquals("abc" , user.getName());
   }
@@ -32,7 +33,7 @@ public class UserDto2UserMapperTest {
   public void shouldEncodePassword() {
     when(passwordService.encryptPassword("unencrypted")).thenReturn("encrypted");
 
-    UserDto dto = new UserDto();
+    UserDto dto = createDefaultDto();
     dto.setPassword("unencrypted");
     User user = mapper.userDtoToUser(dto, "original password");
     assertEquals("encrypted" , user.getPassword());
@@ -40,21 +41,28 @@ public class UserDto2UserMapperTest {
 
   @Test
   public void shouldMapTimes() {
-    UserDto dto = new UserDto();
-    dto.setName("abc");
+    UserDto dto = createDefaultDto();
     Instant expectedCreationDate = Instant.ofEpochMilli(66666660000L);
-    Instant expectedModificationDate = null;
+    Optional<Instant> expectedModificationDate = Optional.empty();
     dto.setCreationDate(expectedCreationDate);
     dto.setLastModified(expectedModificationDate);
 
     User user = mapper.userDtoToUser(dto, "original password");
 
     assertEquals((Long) expectedCreationDate.toEpochMilli(), user.getCreationDate());
-    assertEquals(null, user.getLastModified());
+    assertNull(user.getLastModified());
   }
 
   @Before
   public void init() {
     initMocks(this);
   }
+
+  private UserDto createDefaultDto() {
+    UserDto dto = new UserDto();
+    dto.setName("abc");
+    dto.setCreationDate(Instant.now());
+    dto.setLastModified(Optional.empty());
+    return dto;
+  }
 }
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserV2ResourceTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserV2ResourceTest.java
index d3c332231c..75ecb313f8 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserV2ResourceTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/UserV2ResourceTest.java
@@ -79,6 +79,7 @@ public class UserV2ResourceTest {
     User user = new User();
     user.setName("Neo");
     user.setPassword("redpill");
+    user.setCreationDate(System.currentTimeMillis());
     return user;
   }
 }