diff --git a/package.json b/package.json
index 1ec5d68..b43adb4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "cord_workflow_controller",
-    "version": "0.4.1",
+    "version": "0.5.0",
     "description": "CORD Workflow Controller",
     "main": "src/server.js",
     "scripts": {
diff --git a/src/controllers/eventrouter.js b/src/controllers/eventrouter.js
index 334c08b..548bc48 100644
--- a/src/controllers/eventrouter.js
+++ b/src/controllers/eventrouter.js
@@ -176,17 +176,6 @@
         });
     };
 
-    const updateWorkflowRunStatus = (workflowRunId, taskId, status) => {
-        if(!(workflowRunId in workflowRuns)) {
-            logger.log('warn', `cannot find a workflow run with the id - ${workflowRunId}`);
-            return false;
-        }
-
-        let workflowRun = workflowRuns[workflowRunId];
-        workflowRun.updateTaskStatus(taskId, status);
-        return true;
-    };
-
     const setWorkflowRunKickstarted = (workflowRunId) => {
         if(!(workflowRunId in workflowRuns)) {
             logger.log('warn', `cannot find a workflow run with the id - ${workflowRunId}`);
@@ -295,10 +284,6 @@
     };
 
     const emitEvent = (topic, message) => {
-        // list of workflowIds
-        // to check if there are workflow runs for the events
-        let workflowIdsRunning = [];
-
         logger.log('debug', `event is raised : topic ${topic}, message ${JSON.stringify(message)}`);
 
         // route event to running instances
@@ -306,17 +291,22 @@
             let workflowId = workflowRun.getWorkflowId();
             let workflow = workflows[workflowId];
 
-            // event will be routed to workflow runs that meet following criteria
-            // 1) the workflow is currently interested in the same topic
-            //      (already finished tasks are not counted)
-            // 2) the task's key field and value
-            if(workflowRun.isEventAcceptable(workflow, topic, message)) {
-                //console.log(`event ${topic} is routed to workflow run ${workflowRunId}`);
-                logger.log('debug', `event ${topic} is routed to workflow run ${workflowRunId}`);
-                workflowRun.enqueueEvent(topic, message);
+            if(workflow.isEventAcceptable(topic)) {
+                logger.log('debug', `workflow ${workflowId} accept the event : topic ${topic}`);
 
-                if(!workflowIdsRunning.includes(workflowId)) {
-                    workflowIdsRunning.push(workflowId);
+                // event is acceped if event has
+                // the same key field and its value as workflow_run
+                if(workflowRun.isEventAcceptable(topic, message)) {
+                    logger.log('debug', `workflow run ${workflowRunId} accept the event : \
+                                topic ${topic}, message ${JSON.stringify(message)}`);
+                    workflowRun.updateEventKeyFieldValueFromMessage(topic, message);
+
+                    logger.log('debug', `event ${topic} is routed to workflow run ${workflowRunId}`);
+                    workflowRun.enqueueEvent(topic, message);
+                }
+                else {
+                    logger.log('debug', `workflow run ${workflowRunId} reject the event : \
+                                topic ${topic}, message ${JSON.stringify(message)}`);
                 }
             }
         });
@@ -324,25 +314,21 @@
         // check if the event is a kickstart event
         _.forOwn(workflows, (workflow, workflowId) => {
             if(workflow.isKickstartTopic(topic)) {
-                // check if there is a workflow run for the event
-                // kickstart a workflow if there is no workflows runs for the event
-                if(!workflowIdsRunning.includes(workflowId)) {
-                    // we need to buffer the event until workflow run is brought up
-                    let workflowRun = WorkflowRun.WorkflowRun.makeNewRun(workflow);
-                    workflowRun.updateEventKeyFieldValueFromMessage(topic, message);
+                // we need to buffer the event until workflow run is brought up
+                let workflowRun = WorkflowRun.WorkflowRun.makeNewRun(workflow);
+                workflowRun.updateEventKeyFieldValueFromMessage(topic, message);
 
-                    let workflowRunId = workflowRun.getId();
+                let workflowRunId = workflowRun.getId();
 
-                    // register for management
-                    workflowRuns[workflowRunId] = workflowRun;
+                // register for management
+                workflowRuns[workflowRunId] = workflowRun;
 
-                    // route event
-                    logger.log('debug', `event ${topic} is routed to a new workflow run ${workflowRunId}`);
-                    workflowRun.enqueueEvent(topic, message);
+                // route event
+                logger.log('debug', `event ${topic} is routed to a new workflow run ${workflowRunId}`);
+                workflowRun.enqueueEvent(topic, message);
 
-                    // KICKSTART!
-                    kickstart(workflowId, workflowRunId);
-                }
+                // KICKSTART!
+                kickstart(workflowId, workflowRunId);
             }
         });
 
@@ -692,7 +678,6 @@
         checkWorkflowRun: checkWorkflowRun,
         removeWorkflowRun: removeWorkflowRun,
         clearWorkflowRuns: clearWorkflowRuns,
-        updateWorkflowRunStatus: updateWorkflowRunStatus,
         setWorkflowRunKickstarted: setWorkflowRunKickstarted,
         setWorkflowRunStatus: setWorkflowRunStatus
     };
diff --git a/src/controllers/ws_workflowrun.js b/src/controllers/ws_workflowrun.js
index 0f058cb..c947bb9 100644
--- a/src/controllers/ws_workflowrun.js
+++ b/src/controllers/ws_workflowrun.js
@@ -23,84 +23,12 @@
 
     let serviceEvents = {
         // workflow_run -> controller -> workflow_run
-        WORKFLOW_RUN_UPDATE_STATUS: 'cord.workflow.ctlsvc.workflow.run.status',
         WORKFLOW_RUN_COUNT_EVENTS: 'cord.workflow.ctlsvc.workflow.run.count',
         WORKFLOW_RUN_FETCH_EVENT: 'cord.workflow.ctlsvc.workflow.run.fetch',
         // controller -> workflow_run
         WORKFLOW_RUN_NOTIFY_EVENT: 'cord.workflow.ctlsvc.workflow.run.notify'
     };
 
-    // WebSocket interface for workflow status update
-    // Message format:
-    // {
-    //     topic: 'cord.workflow.ctlsvc.workflow.run.status',
-    //     message: {
-    //         req_id: <req_id>, // optional
-    //         workflow_id: <workflow_id>,
-    //         workflow_run_id: <workflow_run_id>,
-    //         task_id: <task_id>,
-    //         status: 'begin' or 'end'
-    //     }
-    // }
-    const updateWorkflowRunStatus = (topic, message, cb) => {
-        const eventrouter = require('./eventrouter.js');
-
-        let errorMessage;
-        if(!message) {
-            // error
-            errorMessage = `Message body for topic ${topic} is null or empty`;
-            logger.log('warn', `Return error - ${errorMessage}`);
-            cb(errorMessage, false);
-            return;
-        }
-
-        if(!('workflow_id' in message)) {
-            // error
-            errorMessage = `workflow_id field is not in message body - ${message}`;
-            logger.log('warn', `Return error - ${errorMessage}`);
-            cb(errorMessage, false);
-            return;
-        }
-
-        if(!('workflow_run_id' in message)) {
-            // error
-            errorMessage = `workflow_run_id field is not in message body - ${message}`;
-            logger.log('warn', `Return error - ${errorMessage}`);
-            cb(errorMessage, false);
-            return;
-        }
-
-        if(!('task_id' in message)) {
-            // error
-            errorMessage = `task_id field is not in message body - ${message}`;
-            logger.log('warn', `Return error - ${errorMessage}`);
-            cb(errorMessage, false);
-            return;
-        }
-
-        if(!('status' in message)) {
-            // error
-            errorMessage = `status field is not in message body - ${message}`;
-            logger.log('warn', `Return error - ${errorMessage}`);
-            cb(errorMessage, false);
-            return;
-        }
-
-        let result = eventrouter.updateWorkflowRunStatus(
-            message.workflow_run_id,
-            message.task_id,
-            message.status.toLowerCase()
-        );
-        if(!result) {
-            errorMessage = `failed to update workflow run status ${message.workflow_run_id}`;
-            cb(errorMessage, false);
-        }
-        else {
-            cb(null, true);
-        }
-        return;
-    };
-
     // WebSocket interface for counting queued events
     // Message format:
     // {
@@ -220,10 +148,6 @@
 
     const getRouter = () => {
         return {
-            updateWorkflowRunStatus: {
-                topic: serviceEvents.WORKFLOW_RUN_UPDATE_STATUS,
-                handler: updateWorkflowRunStatus
-            },
             countQueuedEvents: {
                 topic: serviceEvents.WORKFLOW_RUN_COUNT_EVENTS,
                 handler: countQueuedEvents
diff --git a/src/types/workflow.js b/src/types/workflow.js
index 11ace2f..8ced05b 100644
--- a/src/types/workflow.js
+++ b/src/types/workflow.js
@@ -121,7 +121,6 @@
         getTopics() {
             let allTopics = [];
             _.forOwn(this.topics, (_tasks, topic) => {
-                // value is an array
                 if(!allTopics.includes(topic)) {
                     allTopics.push(topic);
                 }
@@ -129,6 +128,20 @@
             return allTopics;
         }
 
+        isEventAcceptable(topic) {
+            for(let key in this.topics) {
+                if (!this.topics.hasOwnProperty(key)) {
+                    continue;
+                }
+
+                if(key === topic) {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         getTasksForTopic(topic) {
             if(topic in this.topics) {
                 let workflowTasks = this.topics[topic];
diff --git a/src/types/workflowrun.js b/src/types/workflowrun.js
index 8975490..5666dbb 100644
--- a/src/types/workflowrun.js
+++ b/src/types/workflowrun.js
@@ -20,7 +20,6 @@
 
     const _ = require('lodash');
     const dateformat = require('dateformat');
-    const WorkflowRunTask = require('./workflowruntask.js');
     const logger = require('../config/logger.js');
 
     class WorkflowRun {
@@ -30,11 +29,6 @@
             // workflow id
             this.workflowId = workflowId;
 
-            // workflow run tasks - for storing status
-            // id: task id
-            // value : workflow run task obj
-            this.runTasks = {};
-
             // storing key-field, key-value pairs for <event, workflow run> mapping
             // key: topic
             // value: [{
@@ -73,11 +67,7 @@
             let workflowRun = new WorkflowRun(workflowId, workflowRunId);
 
             let tasks = workflow.getTasks();
-            _.forOwn(tasks, (task, taskId) => {
-                // set run tasks
-                let runTask = new WorkflowRunTask.WorkflowRunTask(taskId);
-                workflowRun.addRunTask(runTask);
-
+            _.forOwn(tasks, (task, _taskId) => {
                 // set key_field / value
                 if(task.isCORDTask()) {
                     workflowRun.setEventKeyFieldValue(task.getTopic(), task.getKeyField(), null); // init
@@ -102,26 +92,6 @@
             return this.workflowId;
         }
 
-        addRunTask(runTask) {
-            this.runTasks[runTask.getTaskId()] = runTask;
-        }
-
-        getRunTask(taskId) {
-            if(taskId in this.runTasks) {
-                return this.runTasks[taskId];
-            }
-            return undefined;
-        }
-
-        getTaskStatus(taskId) {
-            return this.runTasks[taskId].getStatus();
-        }
-
-        updateTaskStatus(taskId, status) {
-            let runTask = this.runTasks[taskId];
-            runTask.setStatus(status);
-        }
-
         setEventKeyFieldValue(topic, field, value=null) {
             let keyFieldValues;
             if(!(topic in this.eventKeyFieldValues)) {
@@ -217,113 +187,10 @@
             return false;
         }
 
-        getFilteredRunTasks(includes, excludes) {
-            // returns tasks with filters
-            let includeStatuses=[];
-            let excludeStatuses=[];
-            let includeAll = false;
-
-            if(includes) {
-                if(Array.isArray(includes)) {
-                    // array
-                    includes.forEach((include) => {
-                        if(!includeStatuses.includes(include)) {
-                            includeStatuses.push(include);
-                        }
-                    });
-                }
-                else {
-                    includeStatuses.push(includes);
-                }
-            }
-            else {
-                // undefined or null
-                // include all
-                includeAll = true;
-            }
-
-            if(excludes) {
-                if(Array.isArray(excludes)) {
-                    // array
-                    excludes.forEach((exclude) => {
-                        if(!excludeStatuses.includes(exclude)) {
-                            excludeStatuses.push(exclude);
-                        }
-                    });
-                }
-                else {
-                    excludeStatuses.push(excludes);
-                }
-            }
-            else {
-                // in this case, nothing will be excluded
-                // leave the array empty
-            }
-
-            let filteredRunTasks = [];
-            _.forOwn(this.runTasks, (runTask, _runTaskId) => {
-                // 'excludes' has a higher priority than 'includes'
-                if(!excludes.includes(runTask.getStatus())) {
-                    if(includeAll || includes.includes(runTask.getStatus())) {
-                        // screen tasks that are not finished
-                        filteredRunTasks.push(runTask);
-                    }
-                }
-            });
-            return filteredRunTasks;
-        }
-
-        getFilteredTopics(workflow, includes, excludes) {
-            // returns topics with filters
-            let filteredRunTasks = this.getFilteredRunTasks(includes, excludes);
-            let filteredTopics = [];
-
-            filteredRunTasks.forEach((runTask) => {
-                let taskId = runTask.getTaskId();
-                let task = workflow.getTask(taskId);
-                let topic = task.getTopic();
-                if(!filteredTopics.includes(topic)) {
-                    filteredTopics.push(topic);
-                }
-            });
-            return filteredTopics;
-        }
-
-        getAllTopics(workflow) {
-            return this.getFilteredTopics(workflow, null, null);
-        }
-
-        getAcceptableTopics(workflow) {
-            // return topics for tasks that are running or to be run in the future
-            // include all tasks that are not ended
-            return this.getFilteredTopics(workflow, null, [WorkflowRunTask.TaskStatus.END]);
-        }
-
-        isTopicAcceptable(workflow, topic) {
-            // get topics of tasks that are not completed yet
-            let filteredTopics = this.getFilteredTopics(
-                workflow,
-                null,
-                [WorkflowRunTask.TaskStatus.END]
-            );
-
-            if(filteredTopics.includes(topic)) {
-                return true;
-            }
-            else {
-                return false;
-            }
-        }
-
-        isEventAcceptable(workflow, topic, message) {
-            // event is acceptable if it meets following criteria
-            // 1) the workflow is currently interested in the same topic
-            //      (finished tasks are not counted)
-            // 2) the task's key field and value
-            if(this.isTopicAcceptable(workflow, topic) &&
-                this.isEventAcceptableByKeyFieldValue(topic, message)) {
-                // update key-field values for my topic
-                this.updateEventKeyFieldValueFromMessage(topic, message);
+        isEventAcceptable(topic, message) {
+            // event is acceped if event has
+            // the same key field and its value as workflow_run
+            if(this.isEventAcceptableByKeyFieldValue(topic, message)) {
                 return true;
             }
 
diff --git a/src/types/workflowruntask.js b/src/types/workflowruntask.js
deleted file mode 100644
index fbaa604..0000000
--- a/src/types/workflowruntask.js
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Copyright 2019-present Open Networking Foundation
-
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
-
- * http://www.apache.org/licenses/LICENSE-2.0
-
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-
-(function () {
-    'use strict';
-
-    const logger = require('../config/logger.js');
-
-    const TaskStatus = {
-        INIT: 'init',
-        BEGIN: 'begin',
-        END: 'end',
-        UNKNOWN: 'unknown'
-    };
-
-    class WorkflowRunTask {
-        constructor(taskId) {
-            this.taskId = taskId;
-            this.status = TaskStatus.UNKNOWN;
-        }
-
-        static parseStatus(strTaskStatus) {
-            if(!strTaskStatus) {
-                return TaskStatus.UNKNOWN;
-            }
-            else if(['i', 'init'].includes(strTaskStatus.toLowerCase())) {
-                return TaskStatus.END;
-            }
-            else if(['b', 'begin', 'start'].includes(strTaskStatus.toLowerCase())) {
-                return TaskStatus.BEGIN;
-            }
-            else if(['e', 'end', 'finish'].includes(strTaskStatus.toLowerCase())) {
-                return TaskStatus.END;
-            }
-            else {
-                return TaskStatus.UNKNOWN;
-            }
-        }
-
-        setTaskId(id) {
-            this.taskId = id;
-        }
-
-        getTaskId() {
-            return this.taskId;
-        }
-
-        setStatus(status) {
-            let taskStatus = WorkflowRunTask.parseStatus(status);
-            this.status = taskStatus;
-        }
-
-        getStatus() {
-            return this.status;
-        }
-
-        validate() {
-            if(!this.taskId) {
-                logger.log('error', 'id is not given');
-                return false;
-            }
-
-            if(!this.status) {
-                logger.log('error', 'status is not given');
-                return false;
-            }
-    
-            return true;
-        }
-    }
-    
-    module.exports = {
-        TaskStatus: TaskStatus,
-        WorkflowRunTask: WorkflowRunTask
-    };
-})();
\ No newline at end of file