diff --git a/plugins/library/src/main/java/com/deploygate/plugins/BaseSdkPlugin.kt b/plugins/library/src/main/java/com/deploygate/plugins/BaseSdkPlugin.kt
index 2e072ea..fe1b960 100644
--- a/plugins/library/src/main/java/com/deploygate/plugins/BaseSdkPlugin.kt
+++ b/plugins/library/src/main/java/com/deploygate/plugins/BaseSdkPlugin.kt
@@ -16,7 +16,7 @@ abstract class BaseSdkPlugin : Plugin<Project> {
         /**
          * sdk/java/com/deploygate/sdk/HostAppTest.java needs to be changed for a new release
          */
-        const val ARTIFACT_VERSION = "4.7.1"
+        const val ARTIFACT_VERSION = "4.8.0"
 
         val JAVA_VERSION = JavaVersion.VERSION_1_7
     }
diff --git a/sample/src/main/AndroidManifest.xml b/sample/src/main/AndroidManifest.xml
index 938dfec..f8cda70 100644
--- a/sample/src/main/AndroidManifest.xml
+++ b/sample/src/main/AndroidManifest.xml
@@ -15,6 +15,9 @@
     <!-- only for sample app -->
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
+    <!-- collecting stats data from app&device -->
+    <uses-permission android:name="com.deploygate.permission.ACCESS_SDK" />
+
     <!--
       If you have multiple processes in your application, or you want to customize SDK initializer,
       you need to add your own Application class here. In this example, the class is
@@ -67,4 +70,8 @@
         <!-- SDK will be initialized through ContentProvider by default -->
         <!-- Please refer to stablereal/AndroidManifest.xml -->
     </application>
+
+    <queries>
+        <provider android:authorities="com.deploygate.external.sdk" />
+    </queries>
 </manifest>
\ No newline at end of file
diff --git a/sample/src/main/java/com/deploygate/sample/App.java b/sample/src/main/java/com/deploygate/sample/App.java
index cce2f7f..6bc710c 100644
--- a/sample/src/main/java/com/deploygate/sample/App.java
+++ b/sample/src/main/java/com/deploygate/sample/App.java
@@ -1,9 +1,11 @@
 package com.deploygate.sample;
 
 import android.app.Application;
+import android.content.res.Configuration;
 import android.os.Bundle;
 import android.util.Log;
 
+import com.deploygate.sdk.CustomAttributes;
 import com.deploygate.sdk.DeployGate;
 import com.deploygate.sdk.DeployGateCallback;
 
@@ -34,6 +36,10 @@ public void onInitialized(boolean isServiceAvailable) {
                 if (isServiceAvailable) {
                     Log.i(TAG, "SDK is available");
                     DeployGate.logInfo("SDK is available");
+
+                    CustomAttributes attrs = DeployGate.getBuildEnvironment();
+                    attrs.putString("build_type", BuildConfig.BUILD_TYPE);
+                    attrs.putString("flavor", BuildConfig.FLAVOR);
                 } else {
                     Log.i(TAG, "SDK is unavailable");
                     DeployGate.logInfo("SDK is unavailable"); // this fails silently
@@ -84,4 +90,14 @@ public void onUpdateAvailable(
         //
         // You can use DeployGate.isAuthorized() later to check the installation is valid or not.
     }
+
+    @Override
+    public void onConfigurationChanged(Configuration newConfig) {
+        super.onConfigurationChanged(newConfig);
+
+        CustomAttributes attrs = DeployGate.getRuntimeExtra();
+        attrs.putString("locale", newConfig.locale.toString());
+        attrs.putInt("orientation", newConfig.orientation);
+        attrs.putFloat("font_scale", newConfig.fontScale);
+    }
 }
diff --git a/sample/src/main/java/com/deploygate/sample/SampleActivity.java b/sample/src/main/java/com/deploygate/sample/SampleActivity.java
index 5e69045..c8894ca 100644
--- a/sample/src/main/java/com/deploygate/sample/SampleActivity.java
+++ b/sample/src/main/java/com/deploygate/sample/SampleActivity.java
@@ -14,6 +14,7 @@
 import android.widget.TextView;
 import android.widget.Toast;
 
+import com.deploygate.sdk.CustomAttributes;
 import com.deploygate.sdk.DeployGate;
 import com.deploygate.sdk.DeployGateCallback;
 
@@ -53,6 +54,15 @@ public void onCreate(Bundle savedInstanceState) {
         mUpdateButton = (Button) findViewById(R.id.updateButton);
         mLogMessage = (EditText) findViewById(R.id.message);
         mDistributionComments = (LinearLayout) findViewById(R.id.distributionComments);
+
+
+        CustomAttributes attrs = DeployGate.getRuntimeExtra();
+        attrs.putString("string", "value");
+        attrs.putInt("int", 123);
+        attrs.putBoolean("boolean", true);
+        attrs.putFloat("float", 1.23f);
+        attrs.putDouble("double", 1.23);
+        attrs.putLong("long", 123L);
     }
 
     @Override
diff --git a/sdk/src/main/java/com/deploygate/sdk/CustomAttributes.java b/sdk/src/main/java/com/deploygate/sdk/CustomAttributes.java
new file mode 100644
index 0000000..d35e7b9
--- /dev/null
+++ b/sdk/src/main/java/com/deploygate/sdk/CustomAttributes.java
@@ -0,0 +1,193 @@
+package com.deploygate.sdk;
+
+import com.deploygate.sdk.internal.Logger;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.regex.Pattern;
+
+/**
+ * This class provides store key-value pairs.
+ * These methods are thread-safe.
+ */
+public final class CustomAttributes {
+
+  private static final String TAG = "CustomAttributes";
+
+  private static final int MAX_ATTRIBUTES_SIZE = 8;
+  private static final Pattern VALID_KEY_PATTERN = Pattern.compile("^[a-z][_a-z0-9]{2,31}$");
+  private static final int MAX_VALUE_LENGTH = 64;
+
+  private final Object mLock;
+  private JSONObject attributes;
+
+  CustomAttributes() {
+    mLock = new Object();
+    attributes = new JSONObject();
+  }
+
+  /**
+   * Put a string value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value value must be non-null and its length must be less than 64.
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putString(String key, String value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Put an int value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value int value
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putInt(String key, int value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Put a long value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value long value
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putLong(String key, long value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Put a float value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value float value
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putFloat(String key, float value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Put a double value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value double value
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putDouble(String key, double value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Put a boolean value with the key.
+   * If the key already exists, the value will be overwritten.
+   * @param key key must be non-null and match the valid pattern.
+   * @param value boolean value
+   * @return true if the value is put successfully, otherwise false.
+   * @see CustomAttributes#VALID_KEY_PATTERN
+   */
+  public boolean putBoolean(String key, boolean value) {
+    return putInternal(key, value);
+  }
+
+  /**
+   * Remove the value with the key.
+   * @param key name of the key to be removed.
+   */
+  public void remove(String key) {
+    synchronized (mLock) {
+      attributes.remove(key);
+    }
+  }
+
+  /**
+   * Remove all key-value pairs.
+   */
+  public void removeAll() {
+    synchronized (mLock) {
+      // recreate new object instead of removing all keys
+      attributes = new JSONObject();
+    }
+  }
+
+  int size() {
+    synchronized (mLock) {
+      return attributes.length();
+    }
+  }
+
+  String getJSONString() {
+    synchronized (mLock) {
+      return attributes.toString();
+    }
+  }
+
+  private boolean putInternal(String key, Object value) {
+    if (!isValidKey(key)) {
+      return false;
+    }
+
+    if (!isValidValue(value)) {
+      return false;
+    }
+
+    synchronized (mLock) {
+      try {
+        attributes.put(key, value);
+
+        if (attributes.length() > MAX_ATTRIBUTES_SIZE) {
+          // rollback put operation
+          attributes.remove(key);
+          Logger.w(TAG, "Attributes already reached max size. Ignored: " + key);
+          return false;
+        }
+      } catch (JSONException e) {
+        Logger.w(TAG, "Failed to put attribute: " + key, e);
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  private boolean isValidKey(String key) {
+    if (key == null || key.equals("true") || key.equals("false") || key.equals("null")) {
+      Logger.w(TAG, "Not allowed key: " + key);
+      return false;
+    }
+
+    if (!VALID_KEY_PATTERN.matcher(key).matches()) {
+      Logger.w(TAG, "Invalid key: " + key);
+      return false;
+    }
+
+    return true;
+  }
+
+  private boolean isValidValue(Object value) {
+    if (value == null) {
+      Logger.w(TAG, "Value is null");
+      return false;
+    }
+
+    if (value instanceof String && ((String) value).length() > MAX_VALUE_LENGTH) {
+      Logger.w(TAG, "Value too long: " + value);
+      return false;
+    } else if (value instanceof String || value instanceof Number || value instanceof Boolean) {
+      return true;
+    } else {
+      // dead code
+      Logger.w(TAG, "Invalid value: " + value);
+      return false;
+    }
+  }
+}
diff --git a/sdk/src/main/java/com/deploygate/sdk/DeployGate.java b/sdk/src/main/java/com/deploygate/sdk/DeployGate.java
index a9e60a7..cdb35bf 100644
--- a/sdk/src/main/java/com/deploygate/sdk/DeployGate.java
+++ b/sdk/src/main/java/com/deploygate/sdk/DeployGate.java
@@ -3,10 +3,13 @@
 import android.app.Application;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
+import android.content.ContentResolver;
+import android.content.ContentValues;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.ServiceConnection;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
@@ -21,6 +24,8 @@
 import com.deploygate.service.IDeployGateSdkService;
 import com.deploygate.service.IDeployGateSdkServiceCallback;
 
+import org.json.JSONObject;
+
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -49,6 +54,11 @@ public class DeployGate {
     private static final String DEPLOYGATE_PACKAGE = "com.deploygate";
     private static final Object sPendingEventLock = new Object();
 
+    private static final Object sLock = new Object();
+    private static CustomAttributes sBuildEnvironment;
+    private static CustomAttributes sRuntimeExtra;
+    private static CustomAttributes sSdkDeviceStates;
+
     private static DeployGate sInstance;
 
     private final Context mApplicationContext;
@@ -127,6 +137,35 @@ public void onEvent(
                 } else {
                     Logger.w("streamed logcat is not supported");
                 }
+            } else if (DeployGateEvent.ACTION_COLLECT_DEVICE_STATES.equals(action)) {
+                Uri targetUri = Uri.parse(extras.getString(DeployGateEvent.EXTRA_TARGET_URI_FOR_REPORT_DEVICE_STATES));
+                Logger.d("collect-device-status event received: %s", targetUri);
+
+                ContentValues cv = new ContentValues();
+
+                String buildEnvironmentJSON = getBuildEnvironment().getJSONString();
+                if (!buildEnvironmentJSON.equals("{}")) {
+                    cv.put(DeployGateEvent.ATTRIBUTE_KEY_BUILD_ENVIRONMENT, buildEnvironmentJSON);
+                }
+
+                String runtimeExtraJSON = getRuntimeExtra().getJSONString();
+                if (!runtimeExtraJSON.equals("{}")) {
+                    cv.put(DeployGateEvent.ATTRIBUTE_KEY_RUNTIME_EXTRAS, runtimeExtraJSON);
+                }
+
+                String sdkDeviceStatusJSON = getSdkDeviceStates().getJSONString();
+                if (!sdkDeviceStatusJSON.equals("{}")) {
+                    cv.put(DeployGateEvent.ATTRIBUTE_KEY_SDK_DEVICE_STATES, sdkDeviceStatusJSON);
+                }
+
+                cv.put(DeployGateEvent.ATTRIBUTE_KEY_EVENT_AT, System.currentTimeMillis());
+
+                try {
+                    ContentResolver cr = mApplicationContext.getContentResolver();
+                    cr.insert(targetUri, cv);
+                } catch (Throwable t) {
+                    Logger.w(t, "failed to report device states");
+                }
             } else {
                 Logger.w("%s is not supported by this sdk version", action);
             }
@@ -1390,4 +1429,49 @@ public static String getDistributionUserName() {
 
         return sInstance.mDistributionUserName;
     }
+
+    public static CustomAttributes getBuildEnvironment() {
+        if (sBuildEnvironment != null) {
+            return sBuildEnvironment;
+        }
+
+        synchronized (sLock) {
+            if (sBuildEnvironment != null) {
+                return sBuildEnvironment;
+            }
+            sBuildEnvironment = new CustomAttributes();
+        }
+
+        return sBuildEnvironment;
+    }
+
+    public static CustomAttributes getRuntimeExtra() {
+        if (sRuntimeExtra != null) {
+            return sRuntimeExtra;
+        }
+
+        synchronized (sLock) {
+            if (sRuntimeExtra != null) {
+                return sRuntimeExtra;
+            }
+            sRuntimeExtra = new CustomAttributes();
+        }
+
+        return sRuntimeExtra;
+    }
+
+    private static CustomAttributes getSdkDeviceStates() {
+        if (sSdkDeviceStates != null) {
+            return sSdkDeviceStates;
+        }
+
+        synchronized (sLock) {
+            if (sSdkDeviceStates != null) {
+                return sSdkDeviceStates;
+            }
+            sSdkDeviceStates = new CustomAttributes();
+        }
+
+        return sSdkDeviceStates;
+    }
 }
diff --git a/sdk/src/main/java/com/deploygate/service/DeployGateEvent.java b/sdk/src/main/java/com/deploygate/service/DeployGateEvent.java
index 8b12a57..ad77118 100644
--- a/sdk/src/main/java/com/deploygate/service/DeployGateEvent.java
+++ b/sdk/src/main/java/com/deploygate/service/DeployGateEvent.java
@@ -8,6 +8,7 @@ public interface DeployGateEvent {
     // namespace:
     //   ACTION => a
     //   EXTRA => e
+    //   ATTRIBUTE_KEY => ak
     //
     // content:
     //   should be hyphen-separated string and be lower cases
@@ -27,6 +28,11 @@ public interface DeployGateEvent {
     public static final String ACTION_COMPOSE_COMMENT = "composeComment";
     public static final String ACTION_VISIBILITY_EVENT = "a.visibility-event";
 
+    /**
+     * @since 4.8.0
+     */
+    public static final String ACTION_COLLECT_DEVICE_STATES = "a.collect-device-states";
+
     public static final String EXTRA_AUTHOR = "author";
     public static final String EXTRA_EXPECTED_AUTHOR = "expectedAuthor";
 
@@ -121,6 +127,31 @@ public interface DeployGateEvent {
      */
     public static final String EXTRA_VISIBILITY_EVENT_ELAPSED_REAL_TIME_IN_NANOS = "e.visibility-event-elapsed-real-time";
 
+    /**
+     * @since 4.8.0
+     */
+    public static final String EXTRA_TARGET_URI_FOR_REPORT_DEVICE_STATES = "e.target-uri-for-report-device-states";
+
+    /**
+     * @since 4.8.0
+     */
+    public static final String ATTRIBUTE_KEY_BUILD_ENVIRONMENT = "ak.build-environment";
+
+    /**
+     * @since 4.8.0
+     */
+    public static final String ATTRIBUTE_KEY_RUNTIME_EXTRAS = "ak.runtime-extras";
+
+    /**
+     * @since 4.8.0
+     */
+    public static final String ATTRIBUTE_KEY_SDK_DEVICE_STATES = "ak.sdk-device-states";
+
+    /**
+     * @since 4.8.0
+     */
+    public static final String ATTRIBUTE_KEY_EVENT_AT = "ak.event-at";
+
     interface VisibilityType {
         int BACKGROUND = 0;
         int FOREGROUND = 1;
diff --git a/sdk/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java b/sdk/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java
new file mode 100644
index 0000000..b75071b
--- /dev/null
+++ b/sdk/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java
@@ -0,0 +1,65 @@
+package com.deploygate.sdk;
+
+import androidx.annotation.NonNull;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.google.common.truth.Truth;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * This test class will make sure all *public* interfaces are defined as expected
+ */
+@RunWith(AndroidJUnit4.class)
+public class CustomAttributesInterfaceTest {
+
+  @NonNull
+  CustomAttributes attributes;
+
+  @Before
+  public void setUp() {
+    attributes = new CustomAttributes();
+  }
+
+  @Test
+  public void putString() {
+    Truth.assertThat(attributes.putString("key", "value")).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void putInt() {
+    Truth.assertThat(attributes.putInt("key", 1)).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void putLong() {
+    Truth.assertThat(attributes.putLong("key", 1L)).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void putFloat() {
+    Truth.assertThat(attributes.putFloat("key", 1.0f)).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void putDouble() {
+    Truth.assertThat(attributes.putDouble("key", 1.0)).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void putBoolean() {
+    Truth.assertThat(attributes.putBoolean("key", true)).isInstanceOf(Boolean.class);
+  }
+
+  @Test
+  public void remove() {
+    attributes.remove("key");
+  }
+
+  @Test
+  public void removeAll() {
+    attributes.removeAll();
+  }
+}
\ No newline at end of file
diff --git a/sdk/src/test/java/com/deploygate/sdk/CustomAttributesTest.java b/sdk/src/test/java/com/deploygate/sdk/CustomAttributesTest.java
new file mode 100644
index 0000000..9ac62eb
--- /dev/null
+++ b/sdk/src/test/java/com/deploygate/sdk/CustomAttributesTest.java
@@ -0,0 +1,203 @@
+package com.deploygate.sdk;
+
+import androidx.annotation.NonNull;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.google.common.truth.Truth;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+@RunWith(AndroidJUnit4.class)
+public class CustomAttributesTest {
+
+  @NonNull
+  CustomAttributes attributes;
+
+  @Before
+  public void setUp() {
+    attributes = new CustomAttributes();
+  }
+
+  @Test
+  public void put__accept_when_valid_key() {
+    Truth.assertThat(attributes.putString("valid", "valid_value1")).isTrue();
+    Truth.assertThat(attributes.putString("valid_underscore", "valid_value2")).isTrue();
+    Truth.assertThat(attributes.putString("valid_1_number", "valid_value3")).isTrue();
+    Truth.assertThat(attributes.putString("min", "valid_value4")).isTrue();
+    Truth.assertThat(attributes.putString("valid_key_with_length_under_32", "valid_value5")).isTrue();
+
+    Truth.assertThat(attributes.putString("ng", "invalid_value1")).isFalse();
+    Truth.assertThat(attributes.putString("true", "invalid_value2")).isFalse();
+    Truth.assertThat(attributes.putString("false", "invalid_value3")).isFalse();
+    Truth.assertThat(attributes.putString("null", "invalid_value4")).isFalse();
+    Truth.assertThat(attributes.putString("invalid-hyphen", "invalid_value5")).isFalse();
+    Truth.assertThat(attributes.putString("invalid#sharp", "invalid_value6")).isFalse();
+    Truth.assertThat(attributes.putString("invalid$dollar", "invalid_value7")).isFalse();
+    Truth.assertThat(attributes.putString("invalid.dot", "invalid_value8")).isFalse();
+    Truth.assertThat(attributes.putString("invalid!bang", "invalid_value9")).isFalse();
+    Truth.assertThat(attributes.putString("invalid*glob", "invalid_value10")).isFalse();
+    Truth.assertThat(attributes.putString("invalidUpperCase", "invalid_value11")).isFalse();
+    Truth.assertThat(attributes.putString("12345", "invalid_value12")).isFalse();
+    Truth.assertThat(attributes.putString("1_invalid_begin_number", "invalid_value13")).isFalse();
+    Truth.assertThat(attributes.putString("invalid_key_with_length_over_32_characters", "invalid_value14")).isFalse();
+  }
+
+  @Test
+  public void put__accept_when_valid_value() {
+    Truth.assertThat(attributes.putString("valid_string", "value")).isTrue();
+    Truth.assertThat(attributes.putInt("valid_int", 1)).isTrue();
+    Truth.assertThat(attributes.putLong("valid_long", 1L)).isTrue();
+    Truth.assertThat(attributes.putFloat("valid_float", 1.1f)).isTrue();
+    Truth.assertThat(attributes.putDouble("valid_double", 1.1)).isTrue();
+    Truth.assertThat(attributes.putBoolean("valid_boolean", true)).isTrue();
+
+    String tooLongString = "this is too long string value. we cannot accept value if size over 64.";
+    Truth.assertThat(attributes.putString("invalid_too_long_string", "this is too long string value. we cannot accept value if size over 64.")).isFalse();
+  }
+
+  @Test
+  public void size() {
+    Truth.assertThat(attributes.size()).isEqualTo(0);
+
+    attributes.putString("key1", "value1");
+    Truth.assertThat(attributes.size()).isEqualTo(1);
+
+    attributes.putString("key1", "overwrite1");
+    Truth.assertThat(attributes.size()).isEqualTo(1);
+
+    attributes.putString("key2", "value2");
+    attributes.putString("key3", "value3");
+    attributes.putString("key4", "value4");
+    attributes.putString("key5", "value5");
+    attributes.putString("key6", "value6");
+    attributes.putString("key7", "value7");
+    attributes.putString("key8", "value8");
+    Truth.assertThat(attributes.size()).isEqualTo(8);
+
+    attributes.putString("key9", "value9");
+    Truth.assertThat(attributes.size()).isEqualTo(8);
+
+    attributes.remove("key1");
+    Truth.assertThat(attributes.size()).isEqualTo(7);
+
+    attributes.removeAll();
+    Truth.assertThat(attributes.size()).isEqualTo(0);
+  }
+
+  @Test
+  public void toJSONString() {
+    Truth.assertThat(attributes.getJSONString()).isEqualTo("{}");
+
+    attributes.putString("string", "value");
+    attributes.putInt("int", Integer.MAX_VALUE);
+    attributes.putLong("long", Long.MAX_VALUE);
+    attributes.putFloat("float", Float.MAX_VALUE);
+    attributes.putDouble("double", Double.MAX_VALUE);
+    attributes.putBoolean("boolean", true);
+
+    String expectedJSON = "{" +
+        "\"string\":\"value\"," +
+        "\"int\":2147483647," +
+        "\"long\":9223372036854775807," +
+        "\"float\":3.4028235E38," +
+        "\"double\":1.7976931348623157E308," +
+        "\"boolean\":true" +
+        "}";
+    Truth.assertThat(attributes.getJSONString()).isEqualTo(expectedJSON);
+
+    attributes.removeAll();
+    attributes.putString("string2", "value2");
+    attributes.putInt("int2", Integer.MIN_VALUE);
+    attributes.putLong("long2", Long.MIN_VALUE);
+    attributes.putFloat("float2", Float.MIN_VALUE);
+    attributes.putDouble("double2", Double.MIN_VALUE);
+    attributes.putBoolean("boolean2", false);
+
+    String expectedJSON2 = "{" +
+        "\"string2\":\"value2\"," +
+        "\"int2\":-2147483648," +
+        "\"long2\":-9223372036854775808," +
+        "\"float2\":1.4E-45," +
+        "\"double2\":4.9E-324," +
+        "\"boolean2\":false" +
+        "}";
+    Truth.assertThat(attributes.getJSONString()).isEqualTo(expectedJSON2);
+  }
+
+  @Test
+  public void not_exceed_max_size() {
+    Truth.assertThat(attributes.putString("key1", "value1")).isTrue();
+    Truth.assertThat(attributes.putString("key2", "value2")).isTrue();
+    Truth.assertThat(attributes.putString("key3", "value3")).isTrue();
+    Truth.assertThat(attributes.putString("key4", "value4")).isTrue();
+    Truth.assertThat(attributes.putString("key5", "value5")).isTrue();
+    Truth.assertThat(attributes.putString("key6", "value6")).isTrue();
+    Truth.assertThat(attributes.putString("key7", "value7")).isTrue();
+    Truth.assertThat(attributes.putString("key8", "value8")).isTrue();
+
+    // allow to overwrite
+    Truth.assertThat(attributes.putString("key1", "overwrite1_1")).isTrue();
+    // not allow to put value with new key because of max size
+    Truth.assertThat(attributes.putString("key9", "value9")).isFalse();
+
+    attributes.remove("key8");
+
+    // allow to put value with new key after remove exists key
+    Truth.assertThat(attributes.putString("key9", "value9")).isTrue();
+    // allow to overwrite
+    Truth.assertThat(attributes.putString("key1", "overwrite1_2")).isTrue();
+    // not allow to put value with new key because of max size
+    Truth.assertThat(attributes.putString("key10", "value10")).isFalse();
+
+    attributes.removeAll();
+
+    // allow to put value less than max size
+    Truth.assertThat(attributes.putString("key1", "another_value1")).isTrue();
+    Truth.assertThat(attributes.putString("key2", "another_value2")).isTrue();
+    Truth.assertThat(attributes.putString("key3", "another_value3")).isTrue();
+    Truth.assertThat(attributes.putString("key4", "another_value4")).isTrue();
+    Truth.assertThat(attributes.putString("key5", "another_value5")).isTrue();
+    Truth.assertThat(attributes.putString("key6", "another_value6")).isTrue();
+    Truth.assertThat(attributes.putString("key7", "another_value7")).isTrue();
+    Truth.assertThat(attributes.putString("key8", "another_value8")).isTrue();
+    Truth.assertThat(attributes.putString("key9", "another_value9")).isFalse();
+  }
+
+  @Test()
+  public void not_exceed_max_size_multi_thread() {
+    // prepare attributes with max size
+    for (int i = 0; i < 8; i++) {
+      attributes.putString("key" + i, "value" + i);
+    }
+
+    // try to put value with multi thread
+    ExecutorService executors = Executors.newCachedThreadPool();
+    for (int i = 0; i < 100; i++) {
+      final int index = i;
+      executors.submit(new Runnable() {
+        @Override
+        public void run() {
+          attributes.putString("key" + index, "value" + index);
+        }
+      });
+    }
+
+    Truth.assertThat(attributes.size()).isEqualTo(8);
+    String expectedJSON = "{" +
+        "\"key0\":\"value0\"," +
+        "\"key1\":\"value1\"," +
+        "\"key2\":\"value2\"," +
+        "\"key3\":\"value3\"," +
+        "\"key4\":\"value4\"," +
+        "\"key5\":\"value5\"," +
+        "\"key6\":\"value6\"," +
+        "\"key7\":\"value7\"" +
+        "}";
+    Truth.assertThat(attributes.getJSONString()).isEqualTo(expectedJSON);
+  }
+}
diff --git a/sdk/src/test/java/com/deploygate/sdk/DeployGateInterfaceTest.java b/sdk/src/test/java/com/deploygate/sdk/DeployGateInterfaceTest.java
index 90622bc..62684ee 100644
--- a/sdk/src/test/java/com/deploygate/sdk/DeployGateInterfaceTest.java
+++ b/sdk/src/test/java/com/deploygate/sdk/DeployGateInterfaceTest.java
@@ -364,4 +364,14 @@ public void composeComment__String() {
     public void getDistributionUserName() {
         Truth.assertThat(DeployGate.getDistributionUserName()).isNull();
     }
+
+    @Test
+    public void getBuildEnvironment() {
+        Truth.assertThat(DeployGate.getBuildEnvironment()).isNotNull();
+    }
+
+    @Test
+    public void getRuntimeExtra() {
+        Truth.assertThat(DeployGate.getRuntimeExtra()).isNotNull();
+    }
 }
diff --git a/sdk/src/test/java/com/deploygate/sdk/HostAppTest.java b/sdk/src/test/java/com/deploygate/sdk/HostAppTest.java
index a4f2999..5793449 100644
--- a/sdk/src/test/java/com/deploygate/sdk/HostAppTest.java
+++ b/sdk/src/test/java/com/deploygate/sdk/HostAppTest.java
@@ -36,7 +36,7 @@ public void default_properties() {
         Truth.assertThat(app.canUseLogcat).isTrue();
         Truth.assertThat(app.packageName).isEqualTo("com.deploygate.sdk.test");
         Truth.assertThat(app.sdkVersion).isEqualTo(4);
-        Truth.assertThat(app.sdkArtifactVersion).isEqualTo("4.7.1");
+        Truth.assertThat(app.sdkArtifactVersion).isEqualTo("4.8.0");
         Truth.assertThat(app.activeFeatureFlags).isEqualTo(FULL_BIT);
         Truth.assertThat(app.canUseDeviceCapture()).isTrue();
     }
diff --git a/sdkMock/src/main/java/com/deploygate/sdk/CustomAttributes.java b/sdkMock/src/main/java/com/deploygate/sdk/CustomAttributes.java
new file mode 100644
index 0000000..cdfc4f2
--- /dev/null
+++ b/sdkMock/src/main/java/com/deploygate/sdk/CustomAttributes.java
@@ -0,0 +1,37 @@
+package com.deploygate.sdk;
+
+public final class CustomAttributes {
+
+  CustomAttributes() {
+  }
+
+  public boolean putString(String key, String value) {
+    return false;
+  }
+
+  public boolean putInt(String key, int value) {
+    return false;
+  }
+
+  public boolean putLong(String key, long value) {
+    return false;
+  }
+
+  public boolean putFloat(String key, float value) {
+    return false;
+  }
+
+  public boolean putDouble(String key, double value) {
+    return false;
+  }
+
+  public boolean putBoolean(String key, boolean value) {
+    return false;
+  }
+
+  public void remove(String key) {
+  }
+
+  public void removeAll() {
+  }
+}
diff --git a/sdkMock/src/main/java/com/deploygate/sdk/DeployGate.java b/sdkMock/src/main/java/com/deploygate/sdk/DeployGate.java
index 22e096f..5d0b765 100644
--- a/sdkMock/src/main/java/com/deploygate/sdk/DeployGate.java
+++ b/sdkMock/src/main/java/com/deploygate/sdk/DeployGate.java
@@ -5,6 +5,8 @@
 
 public class DeployGate {
 
+    private static final CustomAttributes sAttributes = new CustomAttributes();
+
     static void clear() {
     }
 
@@ -179,4 +181,12 @@ public static void composeComment(String defaultComment) {
     public static String getDistributionUserName() {
         return null;
     }
+
+    public static CustomAttributes getBuildEnvironment() {
+        return sAttributes;
+    }
+
+    public static CustomAttributes getRuntimeExtra() {
+        return sAttributes;
+    }
 }
diff --git a/sdkMock/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java b/sdkMock/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java
new file mode 120000
index 0000000..cc4e30b
--- /dev/null
+++ b/sdkMock/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java
@@ -0,0 +1 @@
+../../../../../../../sdk/src/test/java/com/deploygate/sdk/CustomAttributesInterfaceTest.java
\ No newline at end of file