diff --git a/app/build.gradle b/app/build.gradle
index 0342379a8..4a3640387 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -79,6 +79,8 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "com.android.support:appcompat-v7:${supportLibraryVersion}"
     implementation "com.android.support:design:${supportLibraryVersion}"
+    implementation 'com.android.support.constraint:constraint-layout:1.1.1'
+
 
     implementation 'com.android.support:multidex:1.0.3'
 
diff --git a/app/src/main/java/com/nextcloud/talk/activities/CallActivity.java b/app/src/main/java/com/nextcloud/talk/activities/CallActivity.java
index eda2dd992..b28eeb597 100644
--- a/app/src/main/java/com/nextcloud/talk/activities/CallActivity.java
+++ b/app/src/main/java/com/nextcloud/talk/activities/CallActivity.java
@@ -1348,7 +1348,7 @@ public class CallActivity extends AppCompatActivity {
                 GlideApp.with(this)
                         .asBitmap()
                         .diskCacheStrategy(DiskCacheStrategy.NONE)
-                        .load(ApiUtils.getUrlForAvatarWithName(baseUrl, participantMap.get(session).getUserId(), true))
+                        .load(ApiUtils.getUrlForAvatarWithName(baseUrl, participantMap.get(session).getUserId(), R.dimen.avatar_size_big))
                         .centerInside()
                         .override(size, size)
                         .apply(RequestOptions.bitmapTransform(new CircleCrop()))
diff --git a/app/src/main/java/com/nextcloud/talk/adapters/items/AdvancedUserItem.java b/app/src/main/java/com/nextcloud/talk/adapters/items/AdvancedUserItem.java
index 15d7d5fbd..7ae6dcb20 100644
--- a/app/src/main/java/com/nextcloud/talk/adapters/items/AdvancedUserItem.java
+++ b/app/src/main/java/com/nextcloud/talk/adapters/items/AdvancedUserItem.java
@@ -123,7 +123,7 @@ public class AdvancedUserItem extends AbstractFlexibleItem<AdvancedUserItem.User
         if (userEntity.getBaseUrl().startsWith("http://") || userEntity.getBaseUrl().startsWith("https://")) {
             holder.avatarImageView.setVisibility(View.VISIBLE);
             GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(userEntity.getBaseUrl(),
-                    participant.getUserId(), false), new LazyHeaders.Builder()
+                    participant.getUserId(), R.dimen.avatar_size), new LazyHeaders.Builder()
                     .setHeader("Accept", "image/*")
                     .setHeader("User-Agent", ApiUtils.getUserAgent())
                     .build());
diff --git a/app/src/main/java/com/nextcloud/talk/adapters/items/CallItem.java b/app/src/main/java/com/nextcloud/talk/adapters/items/CallItem.java
index c2027ccf3..f2a26e89d 100644
--- a/app/src/main/java/com/nextcloud/talk/adapters/items/CallItem.java
+++ b/app/src/main/java/com/nextcloud/talk/adapters/items/CallItem.java
@@ -131,7 +131,7 @@ public class CallItem extends AbstractFlexibleItem<CallItem.RoomItemViewHolder>
 
                 if (!TextUtils.isEmpty(room.getName())) {
                     GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(userEntity.getBaseUrl(),
-                            room.getName(), false), new LazyHeaders.Builder()
+                            room.getName(), R.dimen.avatar_size), new LazyHeaders.Builder()
                             .setHeader("Accept", "image/*")
                             .setHeader("User-Agent", ApiUtils.getUserAgent())
                             .build());
diff --git a/app/src/main/java/com/nextcloud/talk/adapters/items/MentionAutocompleteItem.java b/app/src/main/java/com/nextcloud/talk/adapters/items/MentionAutocompleteItem.java
index eab6f6f96..58e55306e 100644
--- a/app/src/main/java/com/nextcloud/talk/adapters/items/MentionAutocompleteItem.java
+++ b/app/src/main/java/com/nextcloud/talk/adapters/items/MentionAutocompleteItem.java
@@ -99,7 +99,7 @@ public class MentionAutocompleteItem extends AbstractFlexibleItem<UserItem.UserI
         }
 
         GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(currentUser.getBaseUrl(),
-                userId, false), new LazyHeaders.Builder()
+                userId, R.dimen.avatar_size), new LazyHeaders.Builder()
                 .setHeader("Accept", "image/*")
                 .setHeader("User-Agent", ApiUtils.getUserAgent())
                 .build());
diff --git a/app/src/main/java/com/nextcloud/talk/adapters/items/UserItem.java b/app/src/main/java/com/nextcloud/talk/adapters/items/UserItem.java
index e2a8e655b..99e0bd928 100644
--- a/app/src/main/java/com/nextcloud/talk/adapters/items/UserItem.java
+++ b/app/src/main/java/com/nextcloud/talk/adapters/items/UserItem.java
@@ -122,7 +122,7 @@ public class UserItem extends AbstractFlexibleItem<UserItem.UserItemViewHolder>
         }
 
         GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(userEntity.getBaseUrl(),
-                participant.getUserId(), false), new LazyHeaders.Builder()
+                participant.getUserId(), R.dimen.avatar_size), new LazyHeaders.Builder()
                 .setHeader("Accept", "image/*")
                 .setHeader("User-Agent", ApiUtils.getUserAgent())
                 .build());
diff --git a/app/src/main/java/com/nextcloud/talk/controllers/CallNotificationController.java b/app/src/main/java/com/nextcloud/talk/controllers/CallNotificationController.java
index c47b880cb..316e16545 100644
--- a/app/src/main/java/com/nextcloud/talk/controllers/CallNotificationController.java
+++ b/app/src/main/java/com/nextcloud/talk/controllers/CallNotificationController.java
@@ -262,14 +262,14 @@ public class CallNotificationController extends BaseController {
 
     private void loadAvatar() {
         int avatarSize = Math.round(NextcloudTalkApplication
-                .getSharedApplication().getResources().getDimension(R.dimen.avatar_size_big));
+                .getSharedApplication().getResources().getDimension(R.dimen.avatar_size_very_big));
 
         switch (currentRoom.getType()) {
             case ROOM_TYPE_ONE_TO_ONE_CALL:
                 avatarImageView.setVisibility(View.VISIBLE);
 
                 GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(userBeingCalled.getBaseUrl(),
-                        currentRoom.getName(), true), new LazyHeaders.Builder()
+                        currentRoom.getName(), R.dimen.avatar_size_very_big), new LazyHeaders.Builder()
                         .setHeader("Accept", "image/*")
                         .setHeader("User-Agent", ApiUtils.getUserAgent())
                         .build());
diff --git a/app/src/main/java/com/nextcloud/talk/controllers/SettingsController.java b/app/src/main/java/com/nextcloud/talk/controllers/SettingsController.java
index f23a30e1e..67329b015 100644
--- a/app/src/main/java/com/nextcloud/talk/controllers/SettingsController.java
+++ b/app/src/main/java/com/nextcloud/talk/controllers/SettingsController.java
@@ -499,7 +499,7 @@ public class SettingsController extends BaseController {
         }
 
         GlideUrl glideUrl = new GlideUrl(ApiUtils.getUrlForAvatarWithName(userEntity.getBaseUrl(),
-                avatarId, true), new LazyHeaders.Builder()
+                avatarId, R.dimen.avatar_size_big), new LazyHeaders.Builder()
                 .setHeader("Accept", "image/*")
                 .setHeader("User-Agent", ApiUtils.getUserAgent())
                 .build());
diff --git a/app/src/main/java/com/nextcloud/talk/models/json/chat/ChatMessage.java b/app/src/main/java/com/nextcloud/talk/models/json/chat/ChatMessage.java
index c2101b9a8..ad5f0677d 100644
--- a/app/src/main/java/com/nextcloud/talk/models/json/chat/ChatMessage.java
+++ b/app/src/main/java/com/nextcloud/talk/models/json/chat/ChatMessage.java
@@ -21,6 +21,7 @@ package com.nextcloud.talk.models.json.chat;
 
 import com.bluelinelabs.logansquare.annotation.JsonField;
 import com.bluelinelabs.logansquare.annotation.JsonObject;
+import com.nextcloud.talk.R;
 import com.nextcloud.talk.utils.ApiUtils;
 import com.stfalcon.chatkit.commons.models.IMessage;
 import com.stfalcon.chatkit.commons.models.IUser;
@@ -90,7 +91,7 @@ public class ChatMessage implements IMessage {
 
             @Override
             public String getAvatar() {
-                return ApiUtils.getUrlForAvatarWithName(getBaseUrl(), actorId, false);
+                return ApiUtils.getUrlForAvatarWithName(getBaseUrl(), actorId, R.dimen.avatar_size);
             }
         };
     }
diff --git a/app/src/main/java/com/nextcloud/talk/utils/ApiUtils.java b/app/src/main/java/com/nextcloud/talk/utils/ApiUtils.java
index e20d13222..728a0a6f2 100644
--- a/app/src/main/java/com/nextcloud/talk/utils/ApiUtils.java
+++ b/app/src/main/java/com/nextcloud/talk/utils/ApiUtils.java
@@ -20,6 +20,7 @@
 package com.nextcloud.talk.utils;
 
 import android.net.Uri;
+import android.support.annotation.DimenRes;
 import android.support.annotation.Nullable;
 
 import com.nextcloud.talk.BuildConfig;
@@ -163,16 +164,9 @@ public class ApiUtils {
         return "/status.php";
     }
 
-    public static String getUrlForAvatarWithName(String baseUrl, String name, boolean isLargeAvatar) {
-        int avatarSize;
-
-        if (isLargeAvatar) {
-            avatarSize = Math.round(NextcloudTalkApplication
-                    .getSharedApplication().getResources().getDimension(R.dimen.avatar_size_big));
-        } else {
-            avatarSize = Math.round(NextcloudTalkApplication
-                    .getSharedApplication().getResources().getDimension(R.dimen.avatar_size));
-        }
+    public static String getUrlForAvatarWithName(String baseUrl, String name, @DimenRes int avatarSize) {
+        avatarSize = Math.round(NextcloudTalkApplication
+                                    .getSharedApplication().getResources().getDimension(avatarSize));
 
         return baseUrl + "/index.php/avatar/" + Uri.encode(name) + "/" + avatarSize;
     }
diff --git a/app/src/main/res/layout/controller_call_notification.xml b/app/src/main/res/layout/controller_call_notification.xml
index e8171245f..340457cdf 100644
--- a/app/src/main/res/layout/controller_call_notification.xml
+++ b/app/src/main/res/layout/controller_call_notification.xml
@@ -18,84 +18,90 @@
   ~ You should have received a copy of the GNU General Public License
   ~ along with this program.  If not, see <http://www.gnu.org/licenses/>.
   -->
-
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-                android:layout_width="match_parent"
-                android:layout_height="match_parent"
-                android:background="@color/white">
-
+<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:background="@color/grey950">
 
     <TextView
+        android:id="@+id/incomingCallTextView"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:layout_centerInParent="true"
-        android:layout_alignParentTop="true"
+        android:layout_marginTop="32dp"
         android:text="@string/nc_incoming_call"
         android:textAlignment="center"
-        android:textColor="@color/colorPrimary"
-        android:textSize="20sp"
-        android:layout_marginTop="48dp"
-        android:id="@+id/incomingCallTextView"/>
-
-    <ImageView
-        android:id="@+id/avatarImageView"
-        android:layout_width="@dimen/avatar_size_big"
-        android:layout_height="@dimen/avatar_size_big"
-        android:layout_centerHorizontal="true"
-        android:layout_below="@id/incomingCallTextView"
-        android:layout_margin="16dp"/>
+        android:textColor="@color/white30"
+        android:textSize="16sp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 
     <TextView
         android:id="@+id/conversationNameTextView"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:layout_below="@id/avatarImageView"
-        android:layout_centerInParent="true"
+        android:ellipsize="marquee"
         android:textAlignment="center"
-        android:textColor="@color/colorPrimary"
-        android:textSize="16sp"
-        />
+        android:textColor="@color/white"
+        android:textSize="28sp"
+        app:layout_constraintTop_toBottomOf="@+id/incomingCallTextView"
+        tools:text="Victor Gregorius Magnus" />
 
+    <ImageView
+        android:id="@+id/avatarImageView"
+        android:layout_width="@dimen/avatar_size_very_big"
+        android:layout_height="@dimen/avatar_size_very_big"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.498"
+        tools:src="@color/white" />
 
     <com.nextcloud.talk.utils.MagicFlipView
-        xmlns:app="http://schemas.android.com/apk/res-auto"
         android:id="@+id/callAnswerVoiceOnlyView"
         android:layout_width="60dp"
         android:layout_height="60dp"
-        android:layout_above="@id/callControlHangupView"
-        android:layout_centerHorizontal="true"
-        android:layout_toStartOf="@id/callControlHangupView"
+        android:layout_marginBottom="48dp"
         app:checked="false"
         app:enableInitialAnimation="false"
         app:frontBackgroundColor="@color/colorPrimary"
-        app:frontImage="@drawable/ic_mic_white_24px"/>
+        app:frontImage="@drawable/ic_mic_white_24px"
+        app:layout_anchorGravity="top|center"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.129"
+        app:layout_constraintStart_toStartOf="parent" />
 
     <com.nextcloud.talk.utils.MagicFlipView
-        xmlns:app="http://schemas.android.com/apk/res-auto"
         android:id="@+id/callAnswerCameraView"
         android:layout_width="60dp"
         android:layout_height="60dp"
-        android:layout_above="@id/callControlHangupView"
-        android:layout_toEndOf="@id/callControlHangupView"
+        android:layout_marginBottom="48dp"
         app:checked="false"
         app:enableInitialAnimation="false"
         app:frontBackgroundColor="@color/colorPrimary"
-        app:frontImage="@drawable/ic_videocam_white_24px"/>
+        app:frontImage="@drawable/ic_videocam_white_24px"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.5"
+        app:layout_constraintStart_toStartOf="parent" />
 
 
     <com.nextcloud.talk.utils.MagicFlipView
-        xmlns:app="http://schemas.android.com/apk/res-auto"
         android:id="@+id/callControlHangupView"
         android:layout_width="60dp"
         android:layout_height="60dp"
-        android:layout_alignParentBottom="true"
-        android:layout_centerHorizontal="true"
-        android:layout_marginTop="24dp"
-        android:layout_marginBottom="64dp"
+        android:layout_marginBottom="48dp"
         app:checked="false"
         app:enableInitialAnimation="false"
         app:frontBackgroundColor="@color/nc_darkRed"
-        app:frontImage="@drawable/ic_call_end_white_24px"/>
+        app:frontImage="@drawable/ic_call_end_white_24px"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.87"
+        app:layout_constraintStart_toStartOf="parent" />
 
-
-</RelativeLayout>
\ No newline at end of file
+</android.support.constraint.ConstraintLayout>
diff --git a/app/src/main/res/values-ko/strings.xml b/app/src/main/res/values-ko/strings.xml
index 942d29a2c..30de7c415 100644
--- a/app/src/main/res/values-ko/strings.xml
+++ b/app/src/main/res/values-ko/strings.xml
@@ -28,7 +28,7 @@
     <string name="nc_search">검색</string>
 
     <string name="nc_certificate_dialog_title">인증서 확인</string>
-    <string name="nc_certificate_dialog_text">%1$s에서 %2$s에게 발급한 %3$s부터 %4%s까지 유효한 알 수 없는 인증서를 신뢰하시겠습니까?</string>
+    <string name="nc_certificate_dialog_text">%1$s에서 %2$s에게 발급한 %3$s부터 %4$s까지 유효한 알 수 없는 인증서를 신뢰하시겠습니까?</string>
     <string name="nc_yes">예</string>
     <string name="nc_no">아니요</string>
     <string name="nc_details">자세히</string>
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index c7412376a..03007a602 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -17,5 +17,7 @@
     <color name="nc_light_grey">#E8E8E8</color>
     <color name="grey_600">#757575</color>
     <color name="nc_grey">#D5D5D5</color>
+    <color name="white30">#E9FFFFFF</color>
+    <color name="grey950">#111111</color>
 </resources>
 
diff --git a/app/src/main/res/values/dimens.xml b/app/src/main/res/values/dimens.xml
index 75461c897..f1d21de80 100644
--- a/app/src/main/res/values/dimens.xml
+++ b/app/src/main/res/values/dimens.xml
@@ -16,6 +16,7 @@
     <dimen name="margin_between_elements">8dp</dimen>
     <dimen name="avatar_size">40dp</dimen>
     <dimen name="avatar_size_big">80dp</dimen>
+    <dimen name="avatar_size_very_big">180dp</dimen>
     <dimen name="avatar_corner_radius">20dp</dimen>
 
     <dimen name="chat_text_size">14sp</dimen>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 2264ae148..66f9cbe45 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -113,7 +113,7 @@
     <string name="nc_permissions_settings">Open settings</string>
 
     <!-- Call -->
-    <string name="nc_incoming_call">Incoming call</string>
+    <string name="nc_incoming_call">Incoming call from</string>
     <string name="nc_nick_guest">Guest</string>
     <string name="nc_public_call">New public conversation</string>
     <string name="nc_public_call_explanation">Public conversations let you invite people from outside through a