diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/ActivityInfoProviderService.java b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/ActivityInfoProviderService.java
index 4aba0d8013..104d42828e 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/ActivityInfoProviderService.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/ActivityInfoProviderService.java
@@ -147,11 +147,6 @@ public interface ActivityInfoProviderService {
                             "should be provided in unix format in seconds.",
                     required = true)
             @QueryParam("timestamp") long timestamp,
-            @ApiParam(
-                    name = "If-Modified-Since",
-                    value = "Validates if the requested variant has not been modified since the time specified",
-                    required = false)
-            @HeaderParam("If-Modified-Since") String ifModifiedSince,
             @ApiParam(
                     name = "offset",
                     value = "Starting point within the complete list of items qualified.",
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/ActivityProviderServiceImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/ActivityProviderServiceImpl.java
index c5f2fb728c..9557a78629 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/ActivityProviderServiceImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/ActivityProviderServiceImpl.java
@@ -71,10 +71,9 @@ public class ActivityProviderServiceImpl implements ActivityInfoProviderService
     @Override
     public Response getActivities(
             @QueryParam("timestamp") long timestamp,
-            @HeaderParam("If-Modified-Since") String ifModifiedSince,
             @QueryParam("offset") int offset,
             @QueryParam("limit") int limit) {
-        List<Activity> activities = null;
+        List<Activity> activities;
         DeviceManagementProviderService dmService;
         try {
             dmService = DeviceMgtAPIUtils.getDeviceManagementService();