diff --git a/app/package.json b/app/package.json
index 6bed374..84d044a 100644
--- a/app/package.json
+++ b/app/package.json
@@ -6,7 +6,9 @@
   "scripts": {
     "build": "yarn rebuild && webpack --mode production",
     "dev": "node_modules/.bin/webpack-dev-server --mode development --progress",
-    "rebuild": "cd node_modules/heapdump && node-gyp rebuild --target=7.1.1 --arch=x64 --dist-url=https://atom.io/download/electron || echo Could not build heapdump; cd -"
+    "rebuild": "cd node_modules/heapdump && node-gyp rebuild --target=7.1.1 --arch=x64 --dist-url=https://atom.io/download/electron || echo Could not build heapdump; cd -",
+    "test": "TS_NODE_PROJECT=test/tsconfig.json yarn mochatest",
+    "mochatest": "mocha --require ts-node/register src/**/*.spec.ts"
   },
   "author": "",
   "license": "CC-BY-ND-4.0",
@@ -68,10 +70,12 @@
     "@types/uuid": "^7.0.2",
     "@types/vis": "^4.21.9",
     "awesome-typescript-loader": "^5.2.1",
+    "chai": "^4.2.0",
     "css-loader": "^3.0.0",
     "hard-source-webpack-plugin": "^0.13.1",
     "heapdump": "^0.3.12",
     "html-webpack-plugin": "^4.0.0-beta.5",
+    "mocha": "^7.1.1",
     "node-loader": "^0.6.0",
     "source-map-loader": "^0.2.4",
     "style-loader": "^1",
diff --git a/app/src/actions/ConnectionManager.ts b/app/src/actions/ConnectionManager.ts
index f11e850..3239253 100644
--- a/app/src/actions/ConnectionManager.ts
+++ b/app/src/actions/ConnectionManager.ts
@@ -12,10 +12,11 @@ import { showError } from './Global'
 import { remote } from 'electron'
 import { promises as fsPromise } from 'fs'
 import * as path from 'path'
-
 import { ActionTypes, Action } from '../reducers/ConnectionManager'
+import { Subscription } from '../../../backend/src/DataSource/MqttSource'
+import { connectionsMigrator } from './migrations/Connection'
 
-interface ConnectionDictionary {
+export interface ConnectionDictionary {
   [s: string]: ConnectionOptions
 }
 const storedConnectionsIdentifier: StorageIdentifier<ConnectionDictionary> = {
@@ -27,6 +28,12 @@ export const loadConnectionSettings = () => async (dispatch: Dispatch<any>, getS
   try {
     await ensureConnectionsHaveBeenInitialized()
     connections = await persistentStorage.load(storedConnectionsIdentifier)
+
+    // Apply migrations
+    if (connections && connectionsMigrator.isMigrationNecessary(connections)) {
+      connections = connectionsMigrator.applyMigrations(connections)
+      await persistentStorage.store(storedConnectionsIdentifier, connections)
+    }
   } catch (error) {
     dispatch(showError(error))
   }
@@ -101,13 +108,13 @@ export const updateConnection = (connectionId: string, changeSet: Partial<Connec
   type: ActionTypes.CONNECTION_MANAGER_UPDATE_CONNECTION,
 })
 
-export const addSubscription = (subscription: string, connectionId: string): Action => ({
+export const addSubscription = (subscription: Subscription, connectionId: string): Action => ({
   connectionId,
   subscription,
   type: ActionTypes.CONNECTION_MANAGER_ADD_SUBSCRIPTION,
 })
 
-export const deleteSubscription = (subscription: string, connectionId: string): Action => ({
+export const deleteSubscription = (subscription: Subscription, connectionId: string): Action => ({
   connectionId,
   subscription,
   type: ActionTypes.CONNECTION_MANAGER_DELETE_SUBSCRIPTION,
@@ -174,31 +181,4 @@ async function ensureConnectionsHaveBeenInitialized() {
 
     clearLegacyConnectionOptions()
   }
-
-  // Migrate connections, rewrite dictionary to "keep" it "ordered" (dictionaries do not have a guaranteed order)
-  const mayNeedMigrations = connections && connections['iot.eclipse.org']
-  if (connections && mayNeedMigrations) {
-    const newConnections = {}
-    for (const connection of Object.values(connections)) {
-      addMigratedConnection(newConnections, connection)
-    }
-
-    await persistentStorage.store(storedConnectionsIdentifier, newConnections)
-  }
-}
-
-function addMigratedConnection(newConnections: { [key: string]: ConnectionOptions }, connection: ConnectionOptions) {
-  // The host has been renamed, only change the host if it has not been changed
-  // Also check for ssl since SSL is not yet working
-  if (
-    connection.id === 'iot.eclipse.org' &&
-    connection.host === 'iot.eclipse.org' &&
-    connection.port === 1883 &&
-    !connection.encryption
-  ) {
-    connection.id = 'mqtt.eclipse.org'
-    connection.host = 'mqtt.eclipse.org'
-    connection.name = 'mqtt.eclipse.org'
-  }
-  newConnections[connection.id] = connection
 }
diff --git a/app/src/actions/migrations/Connection.ts b/app/src/actions/migrations/Connection.ts
new file mode 100644
index 0000000..9fc8209
--- /dev/null
+++ b/app/src/actions/migrations/Connection.ts
@@ -0,0 +1,94 @@
+import { ConfigMigrator, Migration } from '../../utils/ConfigMigrator'
+import { ConnectionDictionary } from '../ConnectionManager'
+import { ConnectionOptions } from '../../model/ConnectionOptions'
+
+export interface ConnectionOptionsV0 {
+  type: 'mqtt'
+  id: string
+  host: string
+  protocol: 'mqtt' | 'ws'
+  basePath?: string
+  port: number
+  name: string
+  username?: string
+  password?: string
+  encryption: boolean
+  certValidation: boolean
+  // selfSignedCertificate?: CertificateParameters
+  // clientCertificate?: CertificateParameters
+  // clientKey?: CertificateParameters
+  clientId?: string
+  subscriptions: Array<string>
+}
+
+let migrations: Migration[] = [
+  // iot.eclipse.org ha moved to mqtt.eclipse.org
+  {
+    from: undefined,
+    apply: (connection: ConnectionOptionsV0): ConnectionOptionsV0 => {
+      if (connection.id == 'iot.eclipse.org' && connection.host == 'iot.eclipse.org' && connection.port == 1883) {
+        return {
+          ...connection,
+          id: 'mqtt.eclipse.org',
+          host: 'mqtt.eclipse.org',
+          name: 'mqtt.eclipse.org',
+        }
+      }
+
+      return {
+        ...connection,
+      }
+    },
+  },
+  // Remove stored clientId if it is the default generated client id. This allows to connect multiple instances of mqtt explorer to the same broker.
+  // A randomly generated clientId will be used if no clientId is set.
+  {
+    from: undefined,
+    apply: (connection: ConnectionOptionsV0): ConnectionOptionsV0 => {
+      if (connection.clientId && /mqtt-explorer-[0-9a-f]{8}/.test(connection.clientId)) {
+        return {
+          ...connection,
+          clientId: undefined,
+        }
+      }
+
+      return {
+        ...connection,
+      }
+    },
+  },
+  // Added QoS level to subscription options
+  {
+    from: undefined,
+    apply: (connection: ConnectionOptionsV0): ConnectionOptions => {
+      return {
+        ...connection,
+        configVersion: 1,
+        subscriptions: connection.subscriptions.map(topic => ({ topic, qos: 0 })),
+      }
+    },
+  },
+]
+
+const connectionMigrator = new ConfigMigrator(migrations)
+
+function isMigrationNecessary(connections: ConnectionDictionary): boolean {
+  return Object.values(connections)
+    .map(connection => connectionMigrator.isMigrationNecessary(connection))
+    .reduce((a, b) => a || b, false)
+}
+
+function applyMigrations(connections: ConnectionDictionary): ConnectionDictionary {
+  let newConnectionDictionary: ConnectionDictionary = {}
+  Object.keys(connections).forEach(key => {
+    let newConnection = connectionMigrator.applyMigrations(connections[key]) as any
+    newConnectionDictionary[newConnection.id] = newConnection
+  })
+
+  return newConnectionDictionary
+}
+
+export const connectionsMigrator = {
+  isMigrationNecessary,
+  applyMigrations,
+}
diff --git a/app/src/components/ConnectionSetup/AdvancedConnectionSettings.tsx b/app/src/components/ConnectionSetup/AdvancedConnectionSettings.tsx
index 250c37b..44d2e5a 100644
--- a/app/src/components/ConnectionSetup/AdvancedConnectionSettings.tsx
+++ b/app/src/components/ConnectionSetup/AdvancedConnectionSettings.tsx
@@ -1,7 +1,6 @@
 import * as React from 'react'
+import { useState, useCallback, memo } from 'react'
 import Add from '@material-ui/icons/Add'
-import ClearAdornment from '../helper/ClearAdornment'
-import Delete from '@material-ui/icons/Delete'
 import Lock from '@material-ui/icons/Lock'
 import Undo from '@material-ui/icons/Undo'
 import { bindActionCreators } from 'redux'
@@ -9,8 +8,10 @@ import { connect } from 'react-redux'
 import { connectionManagerActions } from '../../actions'
 import { ConnectionOptions } from '../../model/ConnectionOptions'
 import { Theme, withStyles } from '@material-ui/core/styles'
-
-import { Button, Grid, IconButton, TextField, List, ListItem, ListItemText, Tooltip } from '@material-ui/core'
+import { Button, Grid, TextField, Tooltip } from '@material-ui/core'
+import { QosSelect } from '../QosSelect'
+import { QoS } from '../../../../backend/src/DataSource/MqttSource'
+import Subscriptions from './Subscriptions'
 
 interface Props {
   connection: ConnectionOptions
@@ -18,116 +19,93 @@ interface Props {
   managerActions: typeof connectionManagerActions
 }
 
-interface State {
-  subscription: string
-}
+const ConnectionSettings = memo(function ConnectionSettings(props: Props) {
+  const [qos, setQos] = useState<QoS>(0)
+  const [topic, setTopic] = useState('')
+  const { classes } = props
 
-class ConnectionSettings extends React.Component<Props, State> {
-  constructor(props: any) {
-    super(props)
-    this.state = { subscription: '' }
-  }
-
-  private handleChange = (name: string) => (event: any) => {
-    this.props.managerActions.updateConnection(this.props.connection.id, {
-      [name]: event.target.value,
-    })
-  }
-
-  private renderSubscriptions() {
-    const connection = this.props.connection
-    return connection.subscriptions.map(subscription => (
-      <Subscription
-        deleteAction={() => this.props.managerActions.deleteSubscription(subscription, connection.id)}
-        subscription={subscription}
-        key={subscription}
-      />
-    ))
-  }
-
-  public render() {
-    const { classes } = this.props
-    return (
-      <div>
-        <form className={classes.container} noValidate={true} autoComplete="off">
-          <Grid container={true} spacing={3}>
-            <Grid item={true} xs={10} className={classes.gridPadding}>
-              <TextField
-                className={classes.fullWidth}
-                label="Subscription"
-                margin="normal"
-                onChange={(event: React.ChangeEvent<HTMLInputElement>) =>
-                  this.setState({ subscription: event.target.value })
-                }
-              />
-            </Grid>
-            <Grid item={true} xs={2} className={classes.gridPadding}>
-              <Button
-                className={classes.button}
-                color="secondary"
-                onClick={() =>
-                  this.props.managerActions.addSubscription(this.state.subscription, this.props.connection.id)
-                }
-                variant="contained"
-              >
-                <Add /> Add
-              </Button>
-            </Grid>
-            <Grid item={true} xs={12} style={{ padding: 0 }}>
-              <List className={`${classes.topicList} advanced-connection-settings-topic-list`} component="nav">
-                <div className={classes.list}>{this.renderSubscriptions()}</div>
-              </List>
-            </Grid>
-            <Grid item={true} xs={7} className={classes.gridPadding}>
-              <TextField
-                className={classes.fullWidth}
-                label="MQTT Client ID"
-                margin="normal"
-                value={this.props.connection.clientId}
-                onChange={this.handleChange('clientId')}
-              />
-            </Grid>
-            <Grid item={true} xs={3} className={classes.gridPadding}>
-              <div>
-                <Tooltip title="Manage tls connection certificates" placement="top">
-                  <Button
-                    variant="contained"
-                    className={classes.button}
-                    onClick={() => this.props.managerActions.toggleCertificateSettings()}
-                  >
-                    <Lock /> Certificates
-                  </Button>
-                </Tooltip>
-              </div>
-            </Grid>
-            <Grid item={true} xs={2} className={classes.gridPadding}>
-              <Button
-                variant="contained"
-                className={classes.button}
-                onClick={this.props.managerActions.toggleAdvancedSettings}
-              >
-                <Undo /> Back
-              </Button>
-            </Grid>
-          </Grid>
-        </form>
-      </div>
-    )
-  }
-}
-
-const Subscription = (props: { subscription: string; deleteAction: any }) => {
-  return (
-    <ListItem style={{ padding: '0 0 0 8px' }}>
-      <ListItemText>
-        <IconButton onClick={props.deleteAction} style={{ padding: '6px' }}>
-          <Delete />
-        </IconButton>
-        {props.subscription}
-      </ListItemText>
-    </ListItem>
+  const updateSubscription = useCallback(
+    (event: React.ChangeEvent<HTMLInputElement>) => setTopic(event.target.value),
+    []
   )
-}
+
+  const handleChange = useCallback(
+    (name: string) => (event: any) => {
+      props.managerActions.updateConnection(props.connection.id, {
+        [name]: event.target.value,
+      })
+    },
+    []
+  )
+
+  return (
+    <div>
+      <form className={classes.container} noValidate={true} autoComplete="off">
+        <Grid container={true} spacing={3}>
+          <Grid item={true} xs={8} className={classes.gridPadding}>
+            <TextField
+              className={classes.fullWidth}
+              label="Topic"
+              placeholder="example/topic"
+              margin="normal"
+              value={topic}
+              onChange={updateSubscription}
+            />
+          </Grid>
+          <Grid item={true} xs={2} className={classes.gridPadding}>
+            <div className={classes.qos}>
+              <QosSelect label="QoS" selected={qos} onChange={setQos} />
+            </div>
+          </Grid>
+          <Grid item={true} xs={2} className={classes.gridPadding}>
+            <Button
+              className={classes.button}
+              color="secondary"
+              onClick={() => props.managerActions.addSubscription({ topic, qos }, props.connection.id)}
+              variant="contained"
+            >
+              <Add /> Add
+            </Button>
+          </Grid>
+          <Grid item={true} xs={12} style={{ padding: 0 }}>
+            <Subscriptions connection={props.connection} />
+          </Grid>
+          <Grid item={true} xs={7} className={classes.gridPadding}>
+            <TextField
+              className={classes.fullWidth}
+              label="MQTT Client ID"
+              margin="normal"
+              value={props.connection.clientId}
+              onChange={handleChange('clientId')}
+            />
+          </Grid>
+          <Grid item={true} xs={3} className={classes.gridPadding}>
+            <div>
+              <Tooltip title="Manage tls connection certificates" placement="top">
+                <Button
+                  variant="contained"
+                  className={classes.button}
+                  onClick={() => props.managerActions.toggleCertificateSettings()}
+                >
+                  <Lock /> Certificates
+                </Button>
+              </Tooltip>
+            </div>
+          </Grid>
+          <Grid item={true} xs={2} className={classes.gridPadding}>
+            <Button
+              variant="contained"
+              className={classes.button}
+              onClick={props.managerActions.toggleAdvancedSettings}
+            >
+              <Undo /> Back
+            </Button>
+          </Grid>
+        </Grid>
+      </form>
+    </div>
+  )
+})
 
 const mapDispatchToProps = (dispatch: any) => {
   return {
@@ -142,16 +120,13 @@ const styles = (theme: Theme) => ({
   gridPadding: {
     padding: '0 12px !important',
   },
-  topicList: {
-    height: '180px',
-    overflowY: 'scroll' as 'scroll',
-    margin: '8px 16px',
-    backgroundColor: theme.palette.background.default,
-  },
   button: {
     marginTop: theme.spacing(3),
     float: 'right' as 'right',
   },
+  qos: {
+    marginTop: theme.spacing(1),
+  },
 })
 
 export default connect(undefined, mapDispatchToProps)(withStyles(styles)(ConnectionSettings))
diff --git a/app/src/components/ConnectionSetup/ConnectionSettings.tsx b/app/src/components/ConnectionSetup/ConnectionSettings.tsx
index 8c0506e..c4e67c8 100644
--- a/app/src/components/ConnectionSetup/ConnectionSettings.tsx
+++ b/app/src/components/ConnectionSetup/ConnectionSettings.tsx
@@ -1,7 +1,7 @@
 import ConnectButton from './ConnectButton'
-import Delete from '@material-ui/icons/Delete'
 import React, { useCallback, useState } from 'react'
 import Save from '@material-ui/icons/Save'
+import Delete from '@material-ui/icons/Delete'
 import Settings from '@material-ui/icons/Settings'
 import Visibility from '@material-ui/icons/Visibility'
 import VisibilityOff from '@material-ui/icons/VisibilityOff'
diff --git a/app/src/components/ConnectionSetup/Subscriptions.tsx b/app/src/components/ConnectionSetup/Subscriptions.tsx
new file mode 100644
index 0000000..e210e28
--- /dev/null
+++ b/app/src/components/ConnectionSetup/Subscriptions.tsx
@@ -0,0 +1,90 @@
+import React, { useCallback, useState } from 'react'
+import Delete from '@material-ui/icons/Delete'
+import { connectionManagerActions } from '../../actions'
+import { ConnectionOptions } from '../../model/ConnectionOptions'
+import {
+  IconButton,
+  TableContainer,
+  Table,
+  TableHead,
+  TableRow,
+  TableCell,
+  TableBody,
+  Paper,
+  Theme,
+} from '@material-ui/core'
+import { bindActionCreators } from 'redux'
+import { withStyles } from '@material-ui/styles'
+import { connect } from 'react-redux'
+
+function Subscriptions(props: {
+  classes: any
+  connection: ConnectionOptions
+  managerActions: typeof connectionManagerActions
+}) {
+  const { classes, connection, managerActions } = props
+
+  return (
+    <TableContainer component={Paper} className={`${classes.topicList} advanced-connection-settings-topic-list`}>
+      <Table size="small">
+        <TableHead>
+          <TableRow>
+            <TableCell align="left" padding="checkbox" className={classes.tableTitleCell}></TableCell>
+            <TableCell className={classes.tableTitleCell}>Topic</TableCell>
+            <TableCell align="right" className={classes.tableTitleCell}>
+              QoS
+            </TableCell>
+          </TableRow>
+        </TableHead>
+        <TableBody>
+          {connection.subscriptions.map(subscription => (
+            <TableRow key={subscription.topic + '_qos_' + subscription.qos}>
+              <TableCell align="right" className={classes.tableCell}>
+                <IconButton
+                  onClick={() => managerActions.deleteSubscription(subscription, connection.id)}
+                  style={{ padding: '6px' }}
+                >
+                  <Delete />
+                </IconButton>
+              </TableCell>
+
+              <TableCell component="th" scope="row" className={classes.tableCell}>
+                {subscription.topic}
+              </TableCell>
+              <TableCell align="right" className={classes.tableCell}>
+                {subscription.qos}
+              </TableCell>
+            </TableRow>
+          ))}
+        </TableBody>
+      </Table>
+    </TableContainer>
+  )
+}
+
+const mapDispatchToProps = (dispatch: any) => {
+  return {
+    managerActions: bindActionCreators(connectionManagerActions, dispatch),
+  }
+}
+
+const styles = (theme: Theme) => ({
+  tableCell: {
+    paddingTop: 0,
+    paddingBottom: 0,
+    wordBbreak: 'break-word',
+  },
+  tableTitleCell: {
+    paddingTop: `${theme.spacing(0.5)}px`,
+    paddingBottom: `${theme.spacing(0.5)}px`,
+  },
+  topicList: {
+    height: '196px',
+    overflowY: 'scroll' as 'scroll',
+    margin: `${theme.spacing(1)}px ${theme.spacing(1)}px 0 ${theme.spacing(1)}px`,
+    backgroundColor: theme.palette.background.default,
+    width: 'auto',
+  },
+})
+
+export default connect(undefined, mapDispatchToProps)(withStyles(styles)(Subscriptions))
diff --git a/app/src/components/Sidebar/Publish/QosSelect.tsx b/app/src/components/QosSelect.tsx
similarity index 61%
rename from app/src/components/Sidebar/Publish/QosSelect.tsx
rename to app/src/components/QosSelect.tsx
index d0adce3..9653e7a 100644
--- a/app/src/components/Sidebar/Publish/QosSelect.tsx
+++ b/app/src/components/QosSelect.tsx
@@ -1,18 +1,8 @@
 import * as React from 'react'
 import { TextField, MenuItem, Tooltip } from '@material-ui/core'
-import { connect } from 'react-redux'
-import { AppState } from '../../../reducers'
-import { bindActionCreators } from 'redux'
-import { publishActions } from '../../../actions'
+import { QoS } from '../../../backend/src/DataSource/MqttSource'
 
-interface Props {
-  qos: 0 | 1 | 2
-  actions: {
-    publish: typeof publishActions
-  }
-}
-
-function QosSelect(props: Props) {
+export function QosSelect(props: { selected: QoS; onChange: (value: QoS) => void; label?: string }) {
   const tooltipStyle = { textAlign: 'center' as 'center', width: '100%' }
   const itemStyle = { padding: '0' }
 
@@ -22,16 +12,16 @@ function QosSelect(props: Props) {
       if (value !== 0 && value !== 1 && value !== 2) {
         return
       }
-
-      props.actions.publish.setQoS(value)
+      props.onChange(value)
     },
-    [props.actions.publish]
+    [props.onChange]
   )
 
   return (
     <TextField
       select={true}
-      value={props.qos}
+      label={props.label}
+      value={props.selected}
       margin="normal"
       style={{ margin: '8px 0 8px 8px' }}
       onChange={onChangeQos}
@@ -55,18 +45,4 @@ function QosSelect(props: Props) {
   )
 }
 
-const mapDispatchToProps = (dispatch: any) => {
-  return {
-    actions: {
-      publish: bindActionCreators(publishActions, dispatch),
-    },
-  }
-}
-
-const mapStateToProps = (state: AppState) => {
-  return {
-    qos: state.publish.qos,
-  }
-}
-
-export default connect(mapStateToProps, mapDispatchToProps)(QosSelect)
+export default React.memo(QosSelect)
diff --git a/app/src/components/Sidebar/Publish/QosPublishOption.tsx b/app/src/components/Sidebar/Publish/QosPublishOption.tsx
new file mode 100644
index 0000000..14097cb
--- /dev/null
+++ b/app/src/components/Sidebar/Publish/QosPublishOption.tsx
@@ -0,0 +1,34 @@
+import * as React from 'react'
+import { connect } from 'react-redux'
+import { AppState } from '../../../reducers'
+import { bindActionCreators } from 'redux'
+import { publishActions } from '../../../actions'
+import { QosSelect } from '../../QosSelect'
+import { QoS } from '../../../../../backend/src/DataSource/MqttSource'
+
+interface Props {
+  qos: QoS
+  actions: {
+    publish: typeof publishActions
+  }
+}
+
+function QosPublishOption(props: Props) {
+  return <QosSelect onChange={props.actions.publish.setQoS} selected={props.qos} />
+}
+
+const mapDispatchToProps = (dispatch: any) => {
+  return {
+    actions: {
+      publish: bindActionCreators(publishActions, dispatch),
+    },
+  }
+}
+
+const mapStateToProps = (state: AppState) => {
+  return {
+    qos: state.publish.qos,
+  }
+}
+
+export default connect(mapStateToProps, mapDispatchToProps)(QosPublishOption)
diff --git a/app/src/components/Sidebar/Publish/RetainSwitch.tsx b/app/src/components/Sidebar/Publish/RetainSwitch.tsx
index 6f6a953..fd975f5 100644
--- a/app/src/components/Sidebar/Publish/RetainSwitch.tsx
+++ b/app/src/components/Sidebar/Publish/RetainSwitch.tsx
@@ -1,4 +1,4 @@
-import QosSelect from './QosSelect'
+import QosSelect from './QosPublishOption'
 import React from 'react'
 import { Checkbox, FormControlLabel, Tooltip } from '@material-ui/core'
 import { publishActions } from '../../../actions'
diff --git a/app/src/model/ConnectionOptions.ts b/app/src/model/ConnectionOptions.ts
index 46beba7..8eb9871 100644
--- a/app/src/model/ConnectionOptions.ts
+++ b/app/src/model/ConnectionOptions.ts
@@ -1,5 +1,6 @@
 import { MqttOptions } from '../../../backend/src/DataSource'
 import { v4 } from 'uuid'
+import { Subscription } from '../../../backend/src/DataSource/MqttSource'
 const sha1 = require('sha1')
 
 export interface CertificateParameters {
@@ -7,7 +8,9 @@ export interface CertificateParameters {
   /** @property data base64 encoded data */
   data: string
 }
+
 export interface ConnectionOptions {
+  configVersion: 1
   type: 'mqtt'
   id: string
   host: string
@@ -23,7 +26,7 @@ export interface ConnectionOptions {
   clientCertificate?: CertificateParameters
   clientKey?: CertificateParameters
   clientId?: string
-  subscriptions: Array<string>
+  subscriptions: Array<Subscription>
 }
 
 export function toMqttConnection(options: ConnectionOptions): MqttOptions | undefined {
@@ -52,6 +55,7 @@ function generateClientId() {
 
 export function createEmptyConnection(): ConnectionOptions {
   return {
+    configVersion: 1,
     certValidation: true,
     clientId: generateClientId(),
     id: v4() as string,
@@ -59,7 +63,10 @@ export function createEmptyConnection(): ConnectionOptions {
     encryption: false,
     password: undefined,
     username: undefined,
-    subscriptions: ['#', '$SYS/#'],
+    subscriptions: [
+      { topic: '#', qos: 0 },
+      { topic: '$SYS/#', qos: 0 },
+    ],
     type: 'mqtt',
     host: '',
     port: 1883,
diff --git a/app/src/reducers/ConnectionManager.ts b/app/src/reducers/ConnectionManager.ts
index 5a8f331..a16a746 100644
--- a/app/src/reducers/ConnectionManager.ts
+++ b/app/src/reducers/ConnectionManager.ts
@@ -1,5 +1,6 @@
 import { ConnectionOptions } from '../model/ConnectionOptions'
 import { createReducer } from './lib'
+import { Subscription } from '../../../backend/src/DataSource/MqttSource'
 
 export interface ConnectionManagerState {
   connections: { [s: string]: ConnectionOptions }
@@ -50,13 +51,13 @@ export interface SelectConnection {
 
 export interface AddSubscription {
   type: ActionTypes.CONNECTION_MANAGER_ADD_SUBSCRIPTION
-  subscription: string
+  subscription: Subscription
   connectionId: string
 }
 
 export interface DeleteSubscription {
   type: ActionTypes.CONNECTION_MANAGER_DELETE_SUBSCRIPTION
-  subscription: string
+  subscription: Subscription
   connectionId: string
 }
 
@@ -159,8 +160,12 @@ function addSubscription(state: ConnectionManagerState, action: AddSubscription)
 }
 
 function deleteSubscription(state: ConnectionManagerState, action: AddSubscription): ConnectionManagerState {
+  function subscriptionsEqual(v1: Subscription, v2: Subscription): boolean {
+    return v1.topic == v2.topic && v1.qos == v2.qos
+  }
+
   const connection = state.connections[action.connectionId]
-  const newSubscriptions = connection.subscriptions.filter(s => s !== action.subscription)
+  const newSubscriptions = connection.subscriptions.filter(s => !subscriptionsEqual(s, action.subscription))
 
   return {
     ...state,
diff --git a/app/src/utils/ConfigMigrator.ts b/app/src/utils/ConfigMigrator.ts
new file mode 100644
index 0000000..7663ae4
--- /dev/null
+++ b/app/src/utils/ConfigMigrator.ts
@@ -0,0 +1,34 @@
+export interface Migration {
+  from: number | undefined
+  apply: (config: any) => any
+}
+
+interface MigrationSubject {
+  configVersion: number | undefined
+}
+
+export class ConfigMigrator {
+  private migrations: Migration[]
+
+  constructor(migrations: Migration[]) {
+    this.migrations = migrations
+  }
+
+  public applyMigrations(subject: MigrationSubject): Partial<MigrationSubject> {
+    while (this.isMigrationNecessary(subject)) {
+      subject = this.applyableMigrations(subject)
+        .filter(migration => migration.from === subject.configVersion)
+        .reduce((currentSubject, migration) => migration.apply(currentSubject as any), subject)
+    }
+
+    return subject
+  }
+
+  public isMigrationNecessary(subject: MigrationSubject): boolean {
+    return this.applyableMigrations(subject).length > 0
+  }
+
+  private applyableMigrations(subject: MigrationSubject): Migration[] {
+    return this.migrations.filter(migration => migration.from === subject.configVersion)
+  }
+}
diff --git a/app/src/utils/spec/ConfigMigrator.spec.ts b/app/src/utils/spec/ConfigMigrator.spec.ts
new file mode 100644
index 0000000..bce94f2
--- /dev/null
+++ b/app/src/utils/spec/ConfigMigrator.spec.ts
@@ -0,0 +1,115 @@
+import { expect } from 'chai'
+import { ConfigMigrator } from '../ConfigMigrator'
+import 'mocha'
+
+describe('ConfigMigrator', () => {
+  it('applies migrations to a subject with undefined configVersion', () => {
+    let migrator = new ConfigMigrator([
+      {
+        from: undefined,
+        apply: subject => {
+          return {
+            ...subject,
+            configVersion: 1,
+            drink: 'Beer',
+          }
+        },
+      },
+    ])
+
+    let config = {
+      drink: 'water',
+    }
+
+    let migratedConfig = migrator.applyMigrations(config as any) as any
+
+    expect(migratedConfig.drink).to.eq('Beer')
+    expect(migratedConfig.configVersion).to.eq(1)
+  })
+
+  it('applies multiple migrations from the same version', () => {
+    let migrator = new ConfigMigrator([
+      {
+        from: undefined,
+        apply: subject => {
+          return {
+            ...subject,
+            drink: 'Beer',
+          }
+        },
+      },
+      {
+        from: undefined,
+        apply: subject => {
+          return {
+            ...subject,
+            configVersion: 1,
+          }
+        },
+      },
+    ])
+
+    let config = {
+      drink: 'water',
+    }
+
+    let migratedConfig = migrator.applyMigrations(config as any) as any
+
+    expect(migratedConfig.drink).to.eq('Beer')
+    expect(migratedConfig.configVersion).to.eq(1)
+  })
+
+  it('applies multiple migrations with ascending versions', () => {
+    let migrator = new ConfigMigrator([
+      {
+        from: undefined,
+        apply: subject => {
+          return {
+            ...subject,
+            configVersion: 1,
+          }
+        },
+      },
+      {
+        from: 1,
+        apply: subject => {
+          return {
+            ...subject,
+            configVersion: 2,
+          }
+        },
+      },
+    ])
+
+    let config = {
+      drink: 'water',
+    }
+
+    let migratedConfig = migrator.applyMigrations(config as any)
+
+    expect(migratedConfig.configVersion).to.eq(2)
+  })
+
+  it('does not apply non-matching migrations', () => {
+    let migrator = new ConfigMigrator([
+      {
+        from: 2,
+        apply: subject => {
+          return {
+            ...subject,
+            configVersion: 3,
+          }
+        },
+      },
+    ])
+
+    let config = {
+      configVersion: 10,
+      drink: 'water',
+    }
+
+    let migratedConfig = migrator.applyMigrations(config as any)
+
+    expect(migratedConfig.configVersion).to.eq(10)
+  })
+})
diff --git a/app/src/utils/spec/ConnectionsMigration.spec.ts b/app/src/utils/spec/ConnectionsMigration.spec.ts
new file mode 100644
index 0000000..800d9f2
--- /dev/null
+++ b/app/src/utils/spec/ConnectionsMigration.spec.ts
@@ -0,0 +1,71 @@
+import 'mocha'
+import { expect } from 'chai'
+import { connectionsMigrator } from '../../actions/migrations/Connection'
+
+describe('ConnectionsMigrator', () => {
+  it('applies migrations', () => {
+    let connections: any = {
+      '763b2e5c-c1ed-4c9b-ac9a-0970b3be29a7': {
+        certValidation: true,
+        clientId: 'mqtt-explorer-2783f48c',
+        encryption: false,
+        host: 'nodered',
+        id: '763b2e5c-c1ed-4c9b-ac9a-0970b3be29a7',
+        name: 'nodered',
+        port: 1883,
+        protocol: 'mqtt',
+        subscriptions: ['#', '$SYS/#'],
+        type: 'mqtt',
+      },
+      'iot.eclipse.org': {
+        certValidation: true,
+        clientId: 'mqtt-explorer-d913aad3',
+        encryption: false,
+        host: 'iot.eclipse.org',
+        id: 'iot.eclipse.org',
+        name: 'iot.eclipse.org',
+        port: 1883,
+        protocol: 'mqtt',
+        subscriptions: ['#', '$SYS/#'],
+        type: 'mqtt',
+      },
+    }
+
+    let migratedConnections: any = {
+      '763b2e5c-c1ed-4c9b-ac9a-0970b3be29a7': {
+        configVersion: 1,
+        certValidation: true,
+        clientId: undefined,
+        encryption: false,
+        host: 'nodered',
+        id: '763b2e5c-c1ed-4c9b-ac9a-0970b3be29a7',
+        name: 'nodered',
+        port: 1883,
+        protocol: 'mqtt',
+        subscriptions: [
+          { topic: '#', qos: 0 },
+          { topic: '$SYS/#', qos: 0 },
+        ],
+        type: 'mqtt',
+      },
+      'mqtt.eclipse.org': {
+        configVersion: 1,
+        certValidation: true,
+        clientId: undefined,
+        encryption: false,
+        host: 'mqtt.eclipse.org',
+        id: 'mqtt.eclipse.org',
+        name: 'mqtt.eclipse.org',
+        port: 1883,
+        protocol: 'mqtt',
+        subscriptions: [
+          { topic: '#', qos: 0 },
+          { topic: '$SYS/#', qos: 0 },
+        ],
+        type: 'mqtt',
+      },
+    }
+
+    expect(connectionsMigrator.applyMigrations(connections)).to.deep.eq(migratedConnections)
+  })
+})
diff --git a/app/test/mocha.opts b/app/test/mocha.opts
new file mode 100644
index 0000000..a1b1c79
--- /dev/null
+++ b/app/test/mocha.opts
@@ -0,0 +1,3 @@
+--require ts-node/register
+--require source-map-support/register
+--recursive ./src/**/*.spec.ts
diff --git a/app/test/tsconfig.json b/app/test/tsconfig.json
new file mode 100644
index 0000000..09479fd
--- /dev/null
+++ b/app/test/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "extends": "../tsconfig",
+  "compilerOptions": {
+    "module": "commonjs"
+  }
+}
diff --git a/app/yarn.lock b/app/yarn.lock
index d17ba63..d29195f 100644
--- a/app/yarn.lock
+++ b/app/yarn.lock
@@ -736,6 +736,11 @@ ajv@^6.1.0, ajv@^6.10.2, ajv@^6.12.0:
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
+ansi-colors@3.2.3:
+  version "3.2.3"
+  resolved "https://registry.yarnpkg.com/ansi-colors/-/ansi-colors-3.2.3.tgz#57d35b8686e851e2cc04c403f1c00203976a1813"
+  integrity sha512-LEHHyuhlPY3TmuUYMh2oz89lTShfvgbmzaBcxve9t/9Wuy7Dwf4yoAKcND7KFT1HAQfqZ12qtc+DUrBMeKF9nw==
+
 ansi-colors@^3.0.0:
   version "3.2.4"
   resolved "https://registry.yarnpkg.com/ansi-colors/-/ansi-colors-3.2.4.tgz#e3a3da4bfbae6c86a9c285625de124a234026fbf"
@@ -781,6 +786,14 @@ anymatch@^2.0.0:
     micromatch "^3.1.4"
     normalize-path "^2.1.1"
 
+anymatch@~3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/anymatch/-/anymatch-3.1.1.tgz#c55ecf02185e2469259399310c173ce31233b142"
+  integrity sha512-mM8522psRCqzV+6LhomX5wgp25YVibjh8Wj23I5RPkPppSVSjyKD2A2mBJmWGa+KN7f2D6LNh9jkBCeyLktzjg==
+  dependencies:
+    normalize-path "^3.0.0"
+    picomatch "^2.0.4"
+
 aproba@^1.1.1:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/aproba/-/aproba-1.2.0.tgz#6802e6264efd18c790a1b0d517f0f2627bf2c94a"
@@ -791,6 +804,13 @@ archy@1.0.0:
   resolved "https://registry.yarnpkg.com/archy/-/archy-1.0.0.tgz#f9c8c13757cc1dd7bc379ac77b2c62a5c2868c40"
   integrity sha1-+cjBN1fMHde8N5rHeyxipcKGjEA=
 
+argparse@^1.0.7:
+  version "1.0.10"
+  resolved "https://registry.yarnpkg.com/argparse/-/argparse-1.0.10.tgz#bcd6791ea5ae09725e17e5ad988134cd40b3d911"
+  integrity sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==
+  dependencies:
+    sprintf-js "~1.0.2"
+
 arr-diff@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/arr-diff/-/arr-diff-4.0.0.tgz#d6461074febfec71e7e15235761a329a5dc7c520"
@@ -860,6 +880,11 @@ assert@^1.1.1:
     object-assign "^4.1.1"
     util "0.10.3"
 
+assertion-error@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/assertion-error/-/assertion-error-1.1.0.tgz#e60b6b0e8f301bd97e5375215bda406c85118c0b"
+  integrity sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==
+
 assign-symbols@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/assign-symbols/-/assign-symbols-1.0.0.tgz#59667f41fadd4f20ccbc2bb96b8d4f7f78ec0367"
@@ -1003,6 +1028,11 @@ binary-extensions@^1.0.0:
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.13.1.tgz#598afe54755b2868a5330d2aff9d4ebb53209b65"
   integrity sha512-Un7MIEDdUC5gNpcGDV97op1Ywk748MpHcFTHoYs6qnj1Z3j7I53VG3nwZhKzoBZmbdRNnb6WRdFlwl7tSDuZGw==
 
+binary-extensions@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-2.0.0.tgz#23c0df14f6a88077f5f986c0d167ec03c3d5537c"
+  integrity sha512-Phlt0plgpIIBOGTT/ehfFnbNlfsDEiqmzE2KRXoX1bLIlir4X/MR+zSyBEkL05ffWgnRSf/DXv+WrUAVr93/ow==
+
 bindings@^1.5.0:
   version "1.5.0"
   resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.5.0.tgz#10353c9e945334bc0511a6d90b38fbc7c9c504df"
@@ -1089,11 +1119,23 @@ braces@^2.3.1, braces@^2.3.2:
     split-string "^3.0.2"
     to-regex "^3.0.1"
 
+braces@~3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/braces/-/braces-3.0.2.tgz#3454e1a462ee8d599e236df336cd9ea4f8afe107"
+  integrity sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==
+  dependencies:
+    fill-range "^7.0.1"
+
 brorand@^1.0.1:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/brorand/-/brorand-1.1.0.tgz#12c25efe40a45e3c323eb8675a0a0ce57b22371f"
   integrity sha1-EsJe/kCkXjwyPrhnWgoM5XsiNx8=
 
+browser-stdout@1.3.1:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.1.tgz#baa559ee14ced73452229bad7326467c61fabd60"
+  integrity sha512-qhAVI1+Av2X7qelOfAIYwXONood6XlZE/fXaBSmW/T5SzLAmCgzi+eiWE7fUvbHaeNBQH13UftjpXxsfLkMpgw==
+
 browserify-aes@^1.0.0, browserify-aes@^1.0.4:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/browserify-aes/-/browserify-aes-1.2.0.tgz#326734642f403dabc3003209853bb70ad428ef48"
@@ -1263,6 +1305,18 @@ capture-stack-trace@^1.0.0:
   resolved "https://registry.yarnpkg.com/capture-stack-trace/-/capture-stack-trace-1.0.1.tgz#a6c0bbe1f38f3aa0b92238ecb6ff42c344d4135d"
   integrity sha512-mYQLZnx5Qt1JgB1WEiMCf2647plpGeQ2NMR/5L0HNZzGQo4fuSPnK+wjfPnKZV0aiJDgzmWqqkV/g7JD+DW0qw==
 
+chai@^4.2.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/chai/-/chai-4.2.0.tgz#760aa72cf20e3795e84b12877ce0e83737aa29e5"
+  integrity sha512-XQU3bhBukrOsQCuwZndwGcCVQHyZi53fQ6Ys1Fym7E4olpIqqZZhhoFJoaKVvV17lWQoXYwgWN2nF5crA8J2jw==
+  dependencies:
+    assertion-error "^1.1.0"
+    check-error "^1.0.2"
+    deep-eql "^3.0.1"
+    get-func-name "^2.0.0"
+    pathval "^1.1.0"
+    type-detect "^4.0.5"
+
 chalk@2.4.2, chalk@^2.0.1, chalk@^2.1.0, chalk@^2.4.1, chalk@^2.4.2:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
@@ -1277,11 +1331,31 @@ chalk@2.4.2, chalk@^2.0.1, chalk@^2.1.0, chalk@^2.4.1, chalk@^2.4.2:
   resolved "https://registry.yarnpkg.com/charenc/-/charenc-0.0.2.tgz#c0a1d2f3a7092e03774bfa83f14c0fc5790a8667"
   integrity sha1-wKHS86cJLgN3S/qD8UwPxXkKhmc=
 
+check-error@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/check-error/-/check-error-1.0.2.tgz#574d312edd88bb5dd8912e9286dd6c0aed4aac82"
+  integrity sha1-V00xLt2Iu13YkS6Sht1sCu1KrII=
+
 check-types@^8.0.3:
   version "8.0.3"
   resolved "https://registry.yarnpkg.com/check-types/-/check-types-8.0.3.tgz#3356cca19c889544f2d7a95ed49ce508a0ecf552"
   integrity sha512-YpeKZngUmG65rLudJ4taU7VLkOCTMhNl/u4ctNC56LQS/zJTyNH0Lrtwm1tfTsbLlwvlfsA2d1c8vCf/Kh2KwQ==
 
+chokidar@3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.3.0.tgz#12c0714668c55800f659e262d4962a97faf554a6"
+  integrity sha512-dGmKLDdT3Gdl7fBUe8XK+gAtGmzy5Fn0XkkWQuYxGIgWVPPse2CxFA5mtrlD0TOHaHjEUqkWNyP1XdHoJES/4A==
+  dependencies:
+    anymatch "~3.1.1"
+    braces "~3.0.2"
+    glob-parent "~5.1.0"
+    is-binary-path "~2.1.0"
+    is-glob "~4.0.1"
+    normalize-path "~3.0.0"
+    readdirp "~3.2.0"
+  optionalDependencies:
+    fsevents "~2.1.1"
+
 chokidar@^2.1.8:
   version "2.1.8"
   resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-2.1.8.tgz#804b3a7b6a99358c3c5c61e71d8728f041cff917"
@@ -1975,6 +2049,13 @@ debug@2.2.0:
   dependencies:
     ms "0.7.1"
 
+debug@3.2.6, debug@^3.0.0, debug@^3.1.1, debug@^3.2.5:
+  version "3.2.6"
+  resolved "https://registry.yarnpkg.com/debug/-/debug-3.2.6.tgz#e83d17de16d8a7efb7717edbe5fb10135eee629b"
+  integrity sha512-mel+jf7nrtEl5Pn1Qx46zARXKDpBbvzezse7p7LqINmdoIk8PYP5SySaxEmYv6TZ0JyEKA1hsCId6DIhgITtWQ==
+  dependencies:
+    ms "^2.1.1"
+
 debug@=3.1.0, debug@~3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/debug/-/debug-3.1.0.tgz#5bb5a0672628b64149566ba16819e61518c67261"
@@ -1982,13 +2063,6 @@ debug@=3.1.0, debug@~3.1.0:
   dependencies:
     ms "2.0.0"
 
-debug@^3.0.0, debug@^3.1.1, debug@^3.2.5:
-  version "3.2.6"
-  resolved "https://registry.yarnpkg.com/debug/-/debug-3.2.6.tgz#e83d17de16d8a7efb7717edbe5fb10135eee629b"
-  integrity sha512-mel+jf7nrtEl5Pn1Qx46zARXKDpBbvzezse7p7LqINmdoIk8PYP5SySaxEmYv6TZ0JyEKA1hsCId6DIhgITtWQ==
-  dependencies:
-    ms "^2.1.1"
-
 debug@^4.1.0, debug@^4.1.1, debug@~4.1.0:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/debug/-/debug-4.1.1.tgz#3b72260255109c6b589cee050f1d516139664791"
@@ -2011,6 +2085,13 @@ decode-uri-component@^0.2.0:
   resolved "https://registry.yarnpkg.com/decode-uri-component/-/decode-uri-component-0.2.0.tgz#eb3913333458775cb84cd1a1fae062106bb87545"
   integrity sha1-6zkTMzRYd1y4TNGh+uBiEGu4dUU=
 
+deep-eql@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/deep-eql/-/deep-eql-3.0.1.tgz#dfc9404400ad1c8fe023e7da1df1c147c4b444df"
+  integrity sha512-+QeIQyN5ZuO+3Uk5DYh6/1eKO0m0YmJFGNmFHGACpf1ClL1nmlV/p4gNgbl2pJGxgXb4faqo6UE+M5ACEMyVcw==
+  dependencies:
+    type-detect "^4.0.0"
+
 deep-equal@^1.0.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/deep-equal/-/deep-equal-1.1.1.tgz#b5c98c942ceffaf7cb051e24e1434a25a2e6076a"
@@ -2124,6 +2205,11 @@ diff-match-patch@^1.0.4:
   resolved "https://registry.yarnpkg.com/diff-match-patch/-/diff-match-patch-1.0.4.tgz#6ac4b55237463761c4daf0dc603eb869124744b1"
   integrity sha512-Uv3SW8bmH9nAtHKaKSanOQmj2DnlH65fUpcrMdfdaOxUG02QQ4YGZ8AE7kKOMisF7UqvOlGKVYWRvezdncW9lg==
 
+diff@3.5.0:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
+  integrity sha512-A46qtFgd+g7pDZinpnwiRJtxbC1hpgf0uzP3iG89scHk0AUC7A1TGxf5OiiOUv/JMZR8GOt8hL900hV0bOy5xA==
+
 diff@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/diff/-/diff-4.0.2.tgz#60f3aecb89d5fae520c11aa19efc2bb982aade7d"
@@ -2463,7 +2549,7 @@ escape-html@~1.0.3:
   resolved "https://registry.yarnpkg.com/escape-html/-/escape-html-1.0.3.tgz#0258eae4d3d0c0974de1c169188ef0051d1d1988"
   integrity sha1-Aljq5NPQwJdN4cFpGI7wBR0dGYg=
 
-escape-string-regexp@^1.0.5:
+escape-string-regexp@1.0.5, escape-string-regexp@^1.0.5:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
   integrity sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=
@@ -2476,6 +2562,11 @@ eslint-scope@^4.0.3:
     esrecurse "^4.1.0"
     estraverse "^4.1.1"
 
+esprima@^4.0.0:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.1.tgz#13b04cdb3e6c5d19df91ab6987a8695619b0aa71"
+  integrity sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A==
+
 esrecurse@^4.1.0:
   version "4.2.1"
   resolved "https://registry.yarnpkg.com/esrecurse/-/esrecurse-4.2.1.tgz#007a3b9fdbc2b3bb87e4879ea19c92fdbd3942cf"
@@ -2685,6 +2776,13 @@ fill-range@^4.0.0:
     repeat-string "^1.6.1"
     to-regex-range "^2.1.0"
 
+fill-range@^7.0.1:
+  version "7.0.1"
+  resolved "https://registry.yarnpkg.com/fill-range/-/fill-range-7.0.1.tgz#1919a6a7c75fe38b2c7c77e5198535da9acdda40"
+  integrity sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==
+  dependencies:
+    to-regex-range "^5.0.1"
+
 finalhandler@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/finalhandler/-/finalhandler-1.1.2.tgz#b7e7d000ffd11938d0fdb053506f6ebabe9f587d"
@@ -2707,7 +2805,7 @@ find-cache-dir@^2.0.0, find-cache-dir@^2.1.0:
     make-dir "^2.0.0"
     pkg-dir "^3.0.0"
 
-find-up@^3.0.0:
+find-up@3.0.0, find-up@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/find-up/-/find-up-3.0.0.tgz#49169f1d7993430646da61ecc5ae355c21c97b73"
   integrity sha512-1yD6RmLI1XBfxugvORwlck6f75tYL+iR0jqwsOrOxMZyGYqUuDhJ0l4AXdO1iX/FTs9cBAMEk1gWSEx1kSbylg==
@@ -2724,6 +2822,13 @@ findup-sync@3.0.0:
     micromatch "^3.0.4"
     resolve-dir "^1.0.1"
 
+flat@^4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/flat/-/flat-4.1.0.tgz#090bec8b05e39cba309747f1d588f04dbaf98db2"
+  integrity sha512-Px/TiLIznH7gEDlPXcUD4KnBusa6kR6ayRUVcnEAbreRIuhkqow/mun59BuRXwoYk7ZQOLW1ZM05ilIvK38hFw==
+  dependencies:
+    is-buffer "~2.0.3"
+
 flush-write-stream@^1.0.0:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/flush-write-stream/-/flush-write-stream-1.1.1.tgz#8dd7d873a1babc207d94ead0c2e0e44276ebf2e8"
@@ -2820,6 +2925,11 @@ fsevents@^1.2.7:
     bindings "^1.5.0"
     nan "^2.12.1"
 
+fsevents@~2.1.1:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.1.2.tgz#4c0a1fb34bc68e543b4b82a9ec392bfbda840805"
+  integrity sha512-R4wDiBwZ0KzpgOWetKDug1FZcYhqYnUYKtfZYt4mD5SBz76q0KR4Q9o7GIPamsVPGmW3EYPPJ0dOOjvx32ldZA==
+
 fstream@^1.0.2:
   version "1.0.12"
   resolved "https://registry.yarnpkg.com/fstream/-/fstream-1.0.12.tgz#4e8ba8ee2d48be4f7d0de505455548eae5932045"
@@ -2845,6 +2955,11 @@ get-caller-file@^2.0.1:
   resolved "https://registry.yarnpkg.com/get-caller-file/-/get-caller-file-2.0.5.tgz#4f94412a82db32f36e3b0b9741f8a97feb031f7e"
   integrity sha512-DyFP3BM/3YHTQOCUL/w0OZHR0lpKeGrxotcHWcqNEdnltqFwXVfhEBQ94eIo34AfQpo0rGki4cyIiftY06h2Fg==
 
+get-func-name@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/get-func-name/-/get-func-name-2.0.0.tgz#ead774abee72e20409433a066366023dd6887a41"
+  integrity sha1-6td0q+5y4gQJQzoGY2YCPdaIekE=
+
 get-stream@^4.0.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-4.1.0.tgz#c1b255575f3dc21d59bfc79cd3d2b46b1c3a54b5"
@@ -2872,6 +2987,25 @@ glob-parent@^3.1.0:
     is-glob "^3.1.0"
     path-dirname "^1.0.0"
 
+glob-parent@~5.1.0:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.1.1.tgz#b6c1ef417c4e5663ea498f1c45afac6916bbc229"
+  integrity sha512-FnI+VGOpnlGHWZxthPGR+QhR78fuiK0sNLkHQv+bL9fQi57lNNdquIbna/WrfROrolq8GK5Ek6BiMwqL/voRYQ==
+  dependencies:
+    is-glob "^4.0.1"
+
+glob@7.1.3:
+  version "7.1.3"
+  resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.3.tgz#3960832d3f1574108342dafd3a67b332c0969df1"
+  integrity sha512-vcfuiIxogLV4DlGBHIUOwI0IbrJ8HWPc4MU7HzviGeNho/UJDfi6B5p3sHeWIQ0KGIU0Jpxi5ZHxemQfLkkAwQ==
+  dependencies:
+    fs.realpath "^1.0.0"
+    inflight "^1.0.4"
+    inherits "2"
+    minimatch "^3.0.4"
+    once "^1.3.0"
+    path-is-absolute "^1.0.0"
+
 glob@^5.0.3:
   version "5.0.15"
   resolved "https://registry.yarnpkg.com/glob/-/glob-5.0.15.tgz#1bc936b9e02f4a603fcc222ecf7633d30b8b93b1"
@@ -2988,6 +3122,11 @@ grapheme-splitter@^1.0.4:
   resolved "https://registry.yarnpkg.com/grapheme-splitter/-/grapheme-splitter-1.0.4.tgz#9cf3a665c6247479896834af35cf1dbb4400767e"
   integrity sha512-bzh50DW9kTPM00T8y4o8vQg89Di9oLJVLW/KaOGIXJWP/iqCN6WKYkbNOF04vFLJhwcpYUh9ydh/+5vpOqV4YQ==
 
+growl@1.10.5:
+  version "1.10.5"
+  resolved "https://registry.yarnpkg.com/growl/-/growl-1.10.5.tgz#f2735dc2283674fa67478b10181059355c369e5e"
+  integrity sha512-qBr4OuELkhPenW6goKVXiv47US3clb3/IbuWF9KNKEijAy9oeHxU9IgzjvJhHkUzhaj7rOUD7+YGWqUjLp5oSA==
+
 gunzip-maybe@1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/gunzip-maybe/-/gunzip-maybe-1.2.1.tgz#9aa3dce53c272516c40b2a610a25529bf64ee1bc"
@@ -3106,7 +3245,7 @@ hash.js@^1.0.0, hash.js@^1.0.3:
     inherits "^2.0.3"
     minimalistic-assert "^1.0.1"
 
-he@^1.2.0:
+he@1.2.0, he@^1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/he/-/he-1.2.0.tgz#84ae65fa7eafb165fddb61566ae14baf05664f0f"
   integrity sha512-F/1DnUGPopORZi0ni+CvrCgHQ5FyEAHRLSApuYWMmrbSwoN2Mn/7k+Gl38gJnR7yyDZk6WLXwiGod1JOWNDKGw==
@@ -3464,12 +3603,19 @@ is-binary-path@^1.0.0:
   dependencies:
     binary-extensions "^1.0.0"
 
+is-binary-path@~2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/is-binary-path/-/is-binary-path-2.1.0.tgz#ea1f7f3b80f064236e83470f86c09c254fb45b09"
+  integrity sha512-ZMERYes6pDydyuGidse7OsHxtbI7WVeUEozgR/g7rd0xUimYNlvZRE/K2MgZTjWy725IfelLeVcEM97mmtRGXw==
+  dependencies:
+    binary-extensions "^2.0.0"
+
 is-buffer@^1.1.5:
   version "1.1.6"
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.6.tgz#efaa2ea9daa0d7ab2ea13a97b2b8ad51fefbe8be"
   integrity sha512-NcdALwpXkTm5Zvvbk7owOUSvVvBKDgKP5/ewfXEznmQFfs4ZRmanOeKBTjRVjka3QFoN6XJ+9F3USqfHqTaU5w==
 
-is-buffer@^2.0.2:
+is-buffer@^2.0.2, is-buffer@~2.0.3:
   version "2.0.4"
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-2.0.4.tgz#3e572f23c8411a5cfd9557c849e3665e0b290623"
   integrity sha512-Kq1rokWXOPXWuaMAqZiJW4XxsmD9zGx9q4aePabbn3qCRGedtH7Cm+zV8WETitMfu1wdh+Rvd6w5egwSngUX2A==
@@ -3552,7 +3698,7 @@ is-glob@^3.1.0:
   dependencies:
     is-extglob "^2.1.0"
 
-is-glob@^4.0.0:
+is-glob@^4.0.0, is-glob@^4.0.1, is-glob@~4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/is-glob/-/is-glob-4.0.1.tgz#7567dbe9f2f5e2467bc77ab83c4a29482407a5dc"
   integrity sha512-5G0tKtBTFImOqDnLB2hG6Bp2qcKEFduo4tZu9MT/H6NQv/ghhy30o55ufafxJ/LdH79LLs2Kfrn85TLKyA7BUg==
@@ -3571,6 +3717,11 @@ is-number@^3.0.0:
   dependencies:
     kind-of "^3.0.2"
 
+is-number@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
+  integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
+
 is-obj@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/is-obj/-/is-obj-2.0.0.tgz#473fb05d973705e3fd9620545018ca8e22ef4982"
@@ -3683,6 +3834,14 @@ js-base64@^2.5.1:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
   integrity sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==
 
+js-yaml@3.13.1:
+  version "3.13.1"
+  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.13.1.tgz#aff151b30bfdfa8e49e05da22e7415e9dfa37847"
+  integrity sha512-YfbcO7jXDdyj0DGxYVSlSeQNHbD7XPWvrVWeVUujrQEoZzWJIRrCPoyk6kL6IAjAG2IolMK4T0hNUe0HOUs5Jw==
+  dependencies:
+    argparse "^1.0.7"
+    esprima "^4.0.0"
+
 json-parse-better-errors@^1.0.1, json-parse-better-errors@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/json-parse-better-errors/-/json-parse-better-errors-1.0.2.tgz#bb867cfb3450e69107c131d1c514bab3dc8bcaa9"
@@ -3909,6 +4068,13 @@ lodash@^4.15.0, lodash@^4.17.11, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
   integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
 
+log-symbols@3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-3.0.0.tgz#f3a08516a5dea893336a7dee14d18a1cfdab77c4"
+  integrity sha512-dSkNGuI7iG3mfvDzUuYZyvk5dD9ocYCYzNU6CYDE6+Xqd+gwme6Z00NS3dUh8mq/73HaEtT7m6W+yUPtU6BZnQ==
+  dependencies:
+    chalk "^2.4.2"
+
 log-symbols@^2.1.0:
   version "2.2.0"
   resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-2.2.0.tgz#5740e1c5d6f0dfda4ad9323b5332107ef6b4c40a"
@@ -4109,7 +4275,7 @@ minimalistic-crypto-utils@^1.0.0, minimalistic-crypto-utils@^1.0.1:
   resolved "https://registry.yarnpkg.com/minimalistic-crypto-utils/-/minimalistic-crypto-utils-1.0.1.tgz#f6c00c1c0b082246e5c4d99dfb8c7c083b2b582a"
   integrity sha1-9sAMHAsIIkblxNmd+4x8CDsrWCo=
 
-"minimatch@2 || 3", minimatch@^3.0.4:
+"minimatch@2 || 3", minimatch@3.0.4, minimatch@^3.0.4:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
   integrity sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==
@@ -4158,6 +4324,13 @@ mkdirp-then@1.2.0:
     any-promise "^1.1.0"
     mkdirp "^0.5.0"
 
+mkdirp@0.5.3:
+  version "0.5.3"
+  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.3.tgz#5a514b7179259287952881e94410ec5465659f8c"
+  integrity sha512-P+2gwrFqx8lhew375MQHHeTlY8AuOJSrGf0R5ddkEndUkmwpgUob/vQuBD1V22/Cw1/lJr4x+EjllSezBThzBg==
+  dependencies:
+    minimist "^1.2.5"
+
 "mkdirp@>=0.5 0", mkdirp@^0.5.0, mkdirp@^0.5.1, mkdirp@^0.5.3:
   version "0.5.5"
   resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.5.tgz#d91cefd62d1436ca0f41620e251288d420099def"
@@ -4165,6 +4338,36 @@ mkdirp-then@1.2.0:
   dependencies:
     minimist "^1.2.5"
 
+mocha@^7.1.1:
+  version "7.1.1"
+  resolved "https://registry.yarnpkg.com/mocha/-/mocha-7.1.1.tgz#89fbb30d09429845b1bb893a830bf5771049a441"
+  integrity sha512-3qQsu3ijNS3GkWcccT5Zw0hf/rWvu1fTN9sPvEd81hlwsr30GX2GcDSSoBxo24IR8FelmrAydGC6/1J5QQP4WA==
+  dependencies:
+    ansi-colors "3.2.3"
+    browser-stdout "1.3.1"
+    chokidar "3.3.0"
+    debug "3.2.6"
+    diff "3.5.0"
+    escape-string-regexp "1.0.5"
+    find-up "3.0.0"
+    glob "7.1.3"
+    growl "1.10.5"
+    he "1.2.0"
+    js-yaml "3.13.1"
+    log-symbols "3.0.0"
+    minimatch "3.0.4"
+    mkdirp "0.5.3"
+    ms "2.1.1"
+    node-environment-flags "1.0.6"
+    object.assign "4.1.0"
+    strip-json-comments "2.0.1"
+    supports-color "6.0.0"
+    which "1.3.1"
+    wide-align "1.1.3"
+    yargs "13.3.2"
+    yargs-parser "13.1.2"
+    yargs-unparser "1.6.0"
+
 moment@>=2.13.0, moment@^2.24.0:
   version "2.24.0"
   resolved "https://registry.yarnpkg.com/moment/-/moment-2.24.0.tgz#0d055d53f5052aa653c9f6eb68bb5d12bf5c2b5b"
@@ -4284,6 +4487,14 @@ no-case@^3.0.3:
     lower-case "^2.0.1"
     tslib "^1.10.0"
 
+node-environment-flags@1.0.6:
+  version "1.0.6"
+  resolved "https://registry.yarnpkg.com/node-environment-flags/-/node-environment-flags-1.0.6.tgz#a30ac13621f6f7d674260a54dede048c3982c088"
+  integrity sha512-5Evy2epuL+6TM0lCQGpFIj6KwiEsGh1SrHUhTbNX+sLbBtjidPZFAnVK9y5yU1+h//RitLbRHTIMyxQPtxMdHw==
+  dependencies:
+    object.getownpropertydescriptors "^2.0.3"
+    semver "^5.7.0"
+
 node-forge@0.9.0:
   version "0.9.0"
   resolved "https://registry.yarnpkg.com/node-forge/-/node-forge-0.9.0.tgz#d624050edbb44874adca12bb9a52ec63cb782579"
@@ -4355,7 +4566,7 @@ normalize-path@^2.1.1:
   dependencies:
     remove-trailing-separator "^1.0.1"
 
-normalize-path@^3.0.0:
+normalize-path@^3.0.0, normalize-path@~3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/normalize-path/-/normalize-path-3.0.0.tgz#0dcd69ff23a1c9b11fd0978316644a0388216a65"
   integrity sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA==
@@ -4454,7 +4665,7 @@ object-visit@^1.0.0:
   dependencies:
     isobject "^3.0.0"
 
-object.assign@^4.1.0:
+object.assign@4.1.0, object.assign@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/object.assign/-/object.assign-4.1.0.tgz#968bf1100d7956bb3ca086f006f846b3bc4008da"
   integrity sha512-exHJeq6kBKj58mqGyTQ9DFvrZC/eR6OwxzoM9YRoGBqrXYonaFyGiFMuc9VZrXf7DarreEwMpurG3dd+CNyW5w==
@@ -4718,6 +4929,11 @@ path-to-regexp@0.1.7:
   resolved "https://registry.yarnpkg.com/path-to-regexp/-/path-to-regexp-0.1.7.tgz#df604178005f522f15eb4490e7247a1bfaa67f8c"
   integrity sha1-32BBeABfUi8V60SQ5yR6G/qmf4w=
 
+pathval@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/pathval/-/pathval-1.1.0.tgz#b942e6d4bde653005ef6b71361def8727d0645e0"
+  integrity sha1-uULm1L3mUwBe9rcTYd74cn0GReA=
+
 pbkdf2@^3.0.3:
   version "3.0.17"
   resolved "https://registry.yarnpkg.com/pbkdf2/-/pbkdf2-3.0.17.tgz#976c206530617b14ebb32114239f7b09336e93a6"
@@ -4748,6 +4964,11 @@ performance-now@^2.1.0:
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-2.1.0.tgz#6309f4e0e5fa913ec1c69307ae364b4b377c9e7b"
   integrity sha1-Ywn04OX6kT7BxpMHrjZLSzd8nns=
 
+picomatch@^2.0.4:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.2.tgz#21f333e9b6b8eaff02468f5146ea406d345f4dad"
+  integrity sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==
+
 pify@^2.0.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"
@@ -5234,6 +5455,13 @@ readdirp@^2.2.1:
     micromatch "^3.1.10"
     readable-stream "^2.0.2"
 
+readdirp@~3.2.0:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/readdirp/-/readdirp-3.2.0.tgz#c30c33352b12c96dfb4b895421a49fd5a9593839"
+  integrity sha512-crk4Qu3pmXwgxdSgGhgA/eXiJAPQiX4GMOZZMXnqKxHX7TaoL+3gQVo/WeuAiogr07DpnfjIMpXXa+PAIvwPGQ==
+  dependencies:
+    picomatch "^2.0.4"
+
 redux-batched-actions@0.5:
   version "0.5.0"
   resolved "https://registry.yarnpkg.com/redux-batched-actions/-/redux-batched-actions-0.5.0.tgz#d3f0e359b2a95c7d80bab442df450bfafd57d122"
@@ -5467,7 +5695,7 @@ selfsigned@^1.10.7:
   dependencies:
     node-forge "0.9.0"
 
-"semver@2 || 3 || 4 || 5", "semver@2.x || 3.x || 4 || 5", "semver@4 || 5", semver@^5.1.0, semver@^5.5.0, semver@^5.6.0:
+"semver@2 || 3 || 4 || 5", "semver@2.x || 3.x || 4 || 5", "semver@4 || 5", semver@^5.1.0, semver@^5.5.0, semver@^5.6.0, semver@^5.7.0:
   version "5.7.1"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.7.1.tgz#a954f931aeba508d307bbf069eff0c01c96116f7"
   integrity sha512-sauaDf/PZdVgrLTNYHRtpXa1iRiKcaebiKQ1BJdpQlWH2lCvexQdX55snPFyK7QzpudqbCI0qXFfOasHdyNDGQ==
@@ -5786,6 +6014,11 @@ split-string@^3.0.1, split-string@^3.0.2:
   dependencies:
     extend-shallow "^3.0.0"
 
+sprintf-js@~1.0.2:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/sprintf-js/-/sprintf-js-1.0.3.tgz#04e6926f662895354f3dd015203633b857297e2c"
+  integrity sha1-BOaSb2YolTVPPdAVIDYzuFcpfiw=
+
 ssri@^6.0.1:
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/ssri/-/ssri-6.0.1.tgz#2a3c41b28dd45b62b63676ecb74001265ae9edd8"
@@ -5847,7 +6080,7 @@ string-width@^1.0.1:
     is-fullwidth-code-point "^1.0.0"
     strip-ansi "^3.0.0"
 
-string-width@^2.0.0, string-width@^2.1.1:
+"string-width@^1.0.2 || 2", string-width@^2.0.0, string-width@^2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-2.1.1.tgz#ab93f27a8dc13d28cac815c462143a6d9012ae9e"
   integrity sha512-nOqH59deCq9SRHlxq1Aw85Jnt4w6KvLKqWVik6oA9ZklXLNIOlqg4F2yrT1MVaTjAqvVwdfeZ7w7aCvJD7ugkw==
@@ -5943,6 +6176,11 @@ strip-eof@^1.0.0:
   resolved "https://registry.yarnpkg.com/strip-eof/-/strip-eof-1.0.0.tgz#bb43ff5598a6eb05d89b59fcd129c983313606bf"
   integrity sha1-u0P/VZim6wXYm1n80SnJgzE2Br8=
 
+strip-json-comments@2.0.1:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-2.0.1.tgz#3c531942e908c2697c0ec344858c286c7ca0a60a"
+  integrity sha1-PFMZQukIwml8DsNEhYwobHygpgo=
+
 style-loader@^1:
   version "1.1.4"
   resolved "https://registry.yarnpkg.com/style-loader/-/style-loader-1.1.4.tgz#1ad81283cefe51096756fd62697258edad933230"
@@ -5951,6 +6189,13 @@ style-loader@^1:
     loader-utils "^2.0.0"
     schema-utils "^2.6.5"
 
+supports-color@6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-6.0.0.tgz#76cfe742cf1f41bb9b1c29ad03068c05b4c0e40a"
+  integrity sha512-on9Kwidc1IUQo+bQdhi8+Tijpo0e1SS6RoGo2guUwn5vdaxw8RXOF9Vb2ws+ihWOmh4JnCJOvaziZWP1VABaLg==
+  dependencies:
+    has-flag "^3.0.0"
+
 supports-color@6.1.0, supports-color@^6.1.0:
   version "6.1.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-6.1.0.tgz#0764abc69c63d5ac842dd4867e8d025e880df8f3"
@@ -6090,6 +6335,13 @@ to-regex-range@^2.1.0:
     is-number "^3.0.0"
     repeat-string "^1.6.1"
 
+to-regex-range@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/to-regex-range/-/to-regex-range-5.0.1.tgz#1648c44aae7c8d988a326018ed72f5b4dd0392e4"
+  integrity sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==
+  dependencies:
+    is-number "^7.0.0"
+
 to-regex@^3.0.1, to-regex@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/to-regex/-/to-regex-3.0.2.tgz#13cfdd9b336552f30b51f33a8ae1b42a7a7599ce"
@@ -6120,6 +6372,11 @@ tty-browserify@0.0.0:
   resolved "https://registry.yarnpkg.com/tty-browserify/-/tty-browserify-0.0.0.tgz#a157ba402da24e9bf957f9aa69d524eed42901a6"
   integrity sha1-oVe6QC2iTpv5V/mqadUk7tQpAaY=
 
+type-detect@^4.0.0, type-detect@^4.0.5:
+  version "4.0.8"
+  resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
+  integrity sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==
+
 type-is@~1.6.17, type-is@~1.6.18:
   version "1.6.18"
   resolved "https://registry.yarnpkg.com/type-is/-/type-is-1.6.18.tgz#4e552cd05df09467dcbc4ef739de89f2cf37c131"
@@ -6493,13 +6750,20 @@ which-module@^2.0.0:
   resolved "https://registry.yarnpkg.com/which-module/-/which-module-2.0.0.tgz#d9ef07dce77b9902b8a3a8fa4b31c3e3f7e6e87a"
   integrity sha1-2e8H3Od7mQK4o6j6SzHD4/fm6Ho=
 
-which@^1.2.14, which@^1.2.9, which@^1.3.1:
+which@1.3.1, which@^1.2.14, which@^1.2.9, which@^1.3.1:
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"
   integrity sha512-HxJdYWq1MTIQbJ3nw0cqssHoTNU267KlrDuGZ1WYlxDStUtKUhOaJmh112/TZmHxxUfuJqPXSOm7tDyas0OSIQ==
   dependencies:
     isexe "^2.0.0"
 
+wide-align@1.1.3:
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/wide-align/-/wide-align-1.1.3.tgz#ae074e6bdc0c14a431e804e624549c633b000457"
+  integrity sha512-QGkOQc8XL6Bt5PwnsExKBPuMKBxnGxWWW3fU55Xt4feHozMUhdUMaBCk290qpm/wG5u/RSKzwdAC4i51YigihA==
+  dependencies:
+    string-width "^1.0.2 || 2"
+
 worker-farm@^1.7.0:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/worker-farm/-/worker-farm-1.7.0.tgz#26a94c5391bbca926152002f69b84a4bf772e5a8"
@@ -6591,6 +6855,14 @@ yallist@^3.0.2:
   resolved "https://registry.yarnpkg.com/yallist/-/yallist-3.1.1.tgz#dbb7daf9bfd8bac9ab45ebf602b8cbad0d5d08fd"
   integrity sha512-a4UGQaWPH59mOXUYnAG2ewncQS4i4F43Tv3JoAM+s2VDAmS9NsK8GpDMLrCHPksFT7h3K6TOoUNn2pb7RoXx4g==
 
+yargs-parser@13.1.2, yargs-parser@^13.1.0, yargs-parser@^13.1.2:
+  version "13.1.2"
+  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.2.tgz#130f09702ebaeef2650d54ce6e3e5706f7a4fb38"
+  integrity sha512-3lbsNRf/j+A4QuSZfDRA7HRSfWrzO0YjqTJd5kjAq37Zep1CEgaYmrH9Q3GwPiB9cHyd1Y1UwggGhJGoxipbzg==
+  dependencies:
+    camelcase "^5.0.0"
+    decamelize "^1.2.0"
+
 yargs-parser@^11.1.1:
   version "11.1.1"
   resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-11.1.1.tgz#879a0865973bca9f6bab5cbdf3b1c67ec7d3bcf4"
@@ -6599,13 +6871,14 @@ yargs-parser@^11.1.1:
     camelcase "^5.0.0"
     decamelize "^1.2.0"
 
-yargs-parser@^13.1.0:
-  version "13.1.2"
-  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.2.tgz#130f09702ebaeef2650d54ce6e3e5706f7a4fb38"
-  integrity sha512-3lbsNRf/j+A4QuSZfDRA7HRSfWrzO0YjqTJd5kjAq37Zep1CEgaYmrH9Q3GwPiB9cHyd1Y1UwggGhJGoxipbzg==
+yargs-unparser@1.6.0:
+  version "1.6.0"
+  resolved "https://registry.yarnpkg.com/yargs-unparser/-/yargs-unparser-1.6.0.tgz#ef25c2c769ff6bd09e4b0f9d7c605fb27846ea9f"
+  integrity sha512-W9tKgmSn0DpSatfri0nx52Joq5hVXgeLiqR/5G0sZNDoLZFOr/xjBUDcShCOGNsBnEMNo1KAMBkTej1Hm62HTw==
   dependencies:
-    camelcase "^5.0.0"
-    decamelize "^1.2.0"
+    flat "^4.1.0"
+    lodash "^4.17.15"
+    yargs "^13.3.0"
 
 yargs@12.0.5:
   version "12.0.5"
@@ -6642,6 +6915,22 @@ yargs@13.2.4:
     y18n "^4.0.0"
     yargs-parser "^13.1.0"
 
+yargs@13.3.2, yargs@^13.3.0:
+  version "13.3.2"
+  resolved "https://registry.yarnpkg.com/yargs/-/yargs-13.3.2.tgz#ad7ffefec1aa59565ac915f82dccb38a9c31a2dd"
+  integrity sha512-AX3Zw5iPruN5ie6xGRIDgqkT+ZhnRlZMLMHAs8tg7nRruy2Nb+i5o9bwghAogtM08q1dpr2LVoS8KSTMYpWXUw==
+  dependencies:
+    cliui "^5.0.0"
+    find-up "^3.0.0"
+    get-caller-file "^2.0.1"
+    require-directory "^2.1.1"
+    require-main-filename "^2.0.0"
+    set-blocking "^2.0.0"
+    string-width "^3.0.0"
+    which-module "^2.0.0"
+    y18n "^4.0.0"
+    yargs-parser "^13.1.2"
+
 yeast@0.1.2:
   version "0.1.2"
   resolved "https://registry.yarnpkg.com/yeast/-/yeast-0.1.2.tgz#008e06d8094320c372dbc2f8ed76a0ca6c8ac419"
diff --git a/appveyor.yml b/appveyor.yml
index 2da5ba5..f84d609 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -21,4 +21,3 @@ test_script:
 
 artifacts:
   - path: 'build\clean\build\*.appx'
-
diff --git a/backend/src/DataSource/MqttSource.ts b/backend/src/DataSource/MqttSource.ts
index a7a5ea7..57ac218 100644
--- a/backend/src/DataSource/MqttSource.ts
+++ b/backend/src/DataSource/MqttSource.ts
@@ -12,12 +12,19 @@ export interface MqttOptions {
   tls: boolean
   certValidation: boolean
   clientId?: string
-  subscriptions: Array<string>
+  subscriptions: Array<Subscription>
   certificateAuthority?: string
   clientCertificate?: string
   clientKey?: string
 }
 
+export interface Subscription {
+  topic: string
+  qos: QoS
+}
+
+export type QoS = 0 | 1 | 2
+
 export class MqttSource implements DataSource<MqttOptions> {
   public stateMachine: DataSourceStateMachine = new DataSourceStateMachine()
   private client: Client | undefined
@@ -74,7 +81,7 @@ export class MqttSource implements DataSource<MqttOptions> {
     client.on('connect', () => {
       this.stateMachine.setConnected(true)
       options.subscriptions.forEach(subscription => {
-        client.subscribe(subscription, (err: Error) => {
+        client.subscribe(subscription.topic, { qos: subscription.qos }, (err: Error) => {
           if (err) {
             this.stateMachine.setError(err)
           }