diff --git a/components/app.js b/components/app.js
index ed3063d..8112245 100644
--- a/components/app.js
+++ b/components/app.js
@@ -1,4 +1,4 @@
-import React, { Component } from 'react'
+import React, { useState, useEffect } from 'react'
 import { BackHandler, StyleSheet, View } from 'react-native'
 import PropTypes from 'prop-types'
 
@@ -7,99 +7,59 @@ import { LocalDate } from '@js-joda/core'
 import Header from './header'
 import Menu from './menu'
 import { viewsList } from './views'
-import { isSettingsView, pages } from './pages'
+import { pages } from './pages'
 
-import { headerTitles } from '../i18n/en/labels'
 import setupNotifications from '../lib/notifications'
 import { closeDb } from '../db'
 
-class App extends Component {
-  static propTypes = {
-    date: PropTypes.string,
-    navigate: PropTypes.func,
-    setDate: PropTypes.func,
-    goBack: PropTypes.func,
-    restartApp: PropTypes.func,
-  }
-
-  constructor(props) {
-    super(props)
-
-    this.backHandler = BackHandler.addEventListener(
-      'hardwareBackPress',
-      this.goBack
-    )
-
-    this.state = {
-      date: LocalDate.now().toString(),
-      currentPage: 'Home',
-    }
-
-    setupNotifications(this.navigate, this.setDate)
-  }
-
-  navigate = (page) => {
-    this.setState({ currentPage: page })
-  }
-
-  setDate = (date) => {
-    this.setState({ date })
-  }
-
-  goBack = () => {
-    const { currentPage } = this.state
-
+const App = ({ restartApp }) => {
+  const [date, setDate] = useState(LocalDate.now().toString())
+  const [currentPage, setCurrentPage] = useState('Home')
+  const goBack = () => {
     if (currentPage === 'Home') {
       closeDb()
       BackHandler.exitApp()
     } else {
       const { parent } = pages.find((p) => p.component === currentPage)
-      this.navigate(parent)
+
+      setCurrentPage(parent)
     }
 
     return true
   }
 
-  componentWillUnmount() {
-    this.backHandler.remove()
-  }
-
-  render() {
-    const { goBack, restartApp } = this.props
-    const { date, currentPage } = this.state
-    const { navigate } = this
-
-    if (!currentPage) {
-      return false
-    }
-
-    const Page = viewsList[currentPage]
-    const title = headerTitles[currentPage]
-
-    const isSettingsSubView = isSettingsView(currentPage)
-    const isTemperatureEditView = currentPage === 'TemperatureEditView'
-
-    const headerProps = {
-      title,
-      handleBack: isSettingsSubView ? goBack : null,
-      navigate,
-    }
-
-    const pageProps = {
-      date,
-      setDate: this.setDate,
-      isTemperatureEditView,
-      navigate,
-    }
-
-    return (
-      <View style={styles.container}>
-        <Header {...headerProps} />
-        <Page {...pageProps} restartApp={restartApp} />
-        <Menu currentPage={currentPage} navigate={navigate} />
-      </View>
+  useEffect(() => {
+    const backHandler = BackHandler.addEventListener(
+      'hardwareBackPress',
+      goBack
     )
+
+    return () => backHandler.remove()
+  })
+
+  useEffect(() => setupNotifications(setCurrentPage, setDate), [])
+
+  const Page = viewsList[currentPage]
+  const isTemperatureEditView = currentPage === 'TemperatureEditView'
+  const headerProps = { navigate: setCurrentPage }
+  const pageProps = {
+    date,
+    setDate,
+    isTemperatureEditView,
+    navigate: setCurrentPage,
   }
+
+  return (
+    <View style={styles.container}>
+      <Header {...headerProps} />
+      <Page {...pageProps} restartApp={restartApp} />
+      <Menu currentPage={currentPage} navigate={setCurrentPage} />
+    </View>
+  )
+}
+
+App.propTypes = {
+  restartApp: PropTypes.func,
 }
 
 const styles = StyleSheet.create({
diff --git a/components/calendar.js b/components/calendar.js
index cb01791..02fee6a 100644
--- a/components/calendar.js
+++ b/components/calendar.js
@@ -1,11 +1,10 @@
-import React, { Component } from 'react'
+import React from 'react'
 import PropTypes from 'prop-types'
 import { StyleSheet, View } from 'react-native'
 import { CalendarList } from 'react-native-calendars'
 
 import { getBleedingDaysSortedByDate } from '../db'
 import cycleModule from '../lib/cycle'
-import nothingChanged from '../db/db-unchanged'
 import {
   calendarTheme,
   predictionToCalFormat,
@@ -13,76 +12,45 @@ import {
   todayToCalFormat,
 } from './helpers/calendar'
 
-class CalendarView extends Component {
-  static propTypes = {
-    setDate: PropTypes.func.isRequired,
-    navigate: PropTypes.func.isRequired,
+const CalendarView = ({ setDate, navigate }) => {
+  const bleedingDays = getBleedingDaysSortedByDate()
+  const predictedMenses = cycleModule().getPredictedMenses()
+
+  const passDateToDayView = ({ dateString }) => {
+    setDate(dateString)
+    navigate('CycleDay')
   }
 
-  constructor(props) {
-    super(props)
-    this.bleedingDays = getBleedingDaysSortedByDate()
-    const predictedMenses = cycleModule().getPredictedMenses()
-    this.state = {
-      bleedingDaysInCalFormat: toCalFormat(this.bleedingDays),
-      predictedBleedingDaysInCalFormat: predictionToCalFormat(predictedMenses),
-      todayInCalFormat: todayToCalFormat(),
-    }
+  const markedDates = Object.assign(
+    {},
+    todayToCalFormat(),
+    toCalFormat(bleedingDays),
+    predictionToCalFormat(predictedMenses)
+  )
 
-    this.bleedingDays.addListener(this.setStateWithCalFormattedDays)
-  }
-
-  setStateWithCalFormattedDays = (_, changes) => {
-    if (nothingChanged(changes)) return
-    const predictedMenses = cycleModule().getPredictedMenses()
-    this.setState({
-      bleedingDaysInCalFormat: toCalFormat(this.bleedingDays),
-      predictedBleedingDaysInCalFormat: predictionToCalFormat(predictedMenses),
-      todayInCalFormat: todayToCalFormat(),
-    })
-  }
-
-  componentWillUnmount() {
-    this.bleedingDays.removeListener(this.setStateWithCalFormattedDays)
-  }
-
-  passDateToDayView = (result) => {
-    this.props.setDate(result.dateString)
-    this.props.navigate('CycleDay')
-  }
-
-  render() {
-    const {
-      todayInCalFormat,
-      bleedingDaysInCalFormat,
-      predictedBleedingDaysInCalFormat,
-    } = this.state
-    const markedDates = Object.assign(
-      {},
-      todayInCalFormat,
-      bleedingDaysInCalFormat,
-      predictedBleedingDaysInCalFormat
-    )
-
-    return (
-      <View style={styles.container}>
-        <CalendarList
-          // If firstDay=1 week starts from Monday. Note that dayNames and dayNamesShort should still start from Sunday.
-          firstDay={1}
-          onDayPress={this.passDateToDayView.bind(this)}
-          markedDates={markedDates}
-          markingType="custom"
-          theme={calendarTheme}
-          // Max amount of months allowed to scroll to the past.
-          pastScrollRange={120}
-        />
-      </View>
-    )
-  }
+  return (
+    <View style={styles.container}>
+      <CalendarList
+        // If firstDay=1 week starts from Monday. Note that dayNames and dayNamesShort should still start from Sunday.
+        firstDay={1}
+        onDayPress={passDateToDayView}
+        markedDates={markedDates}
+        markingType="custom"
+        theme={calendarTheme}
+        // Max amount of months allowed to scroll to the past.
+        pastScrollRange={120}
+      />
+    </View>
+  )
 }
 
 const styles = StyleSheet.create({
   container: { flex: 1 },
 })
 
+CalendarView.propTypes = {
+  setDate: PropTypes.func.isRequired,
+  navigate: PropTypes.func.isRequired,
+}
+
 export default CalendarView
diff --git a/components/pages.js b/components/pages.js
index f6dee18..e9f9b6c 100644
--- a/components/pages.js
+++ b/components/pages.js
@@ -3,9 +3,6 @@ import settingsViews from './settings'
 import settingsLabels from '../i18n/en/settings'
 const labels = settingsLabels.menuItems
 
-export const isSettingsView = (page) =>
-  Object.keys(settingsViews).includes(page)
-
 export const pages = [
   {
     component: 'Home',
diff --git a/components/password-prompt.js b/components/password-prompt.js
index bcf6480..8e8e86a 100644
--- a/components/password-prompt.js
+++ b/components/password-prompt.js
@@ -1,4 +1,4 @@
-import React, { Component } from 'react'
+import React, { useEffect, useState } from 'react'
 import PropTypes from 'prop-types'
 import { Alert, StyleSheet, View } from 'react-native'
 import nodejs from 'nodejs-mobile-react-native'
@@ -15,97 +15,82 @@ import { Containers, Spacing } from '../styles'
 
 const cancelButton = { text: shared.cancel, style: 'cancel' }
 
-export default class PasswordPrompt extends Component {
-  static propTypes = {
-    enableShowApp: PropTypes.func.isRequired,
-  }
-
-  constructor(props) {
-    super(props)
-    this.state = { password: null }
-
-    nodejs.channel.addListener('check-pw', this.passHashToDb, this)
-  }
-
-  componentWillUnmount() {
-    nodejs.channel.removeListener('check-pw', this.passHashToDb)
-  }
-
-  onConfirmDeletion = async () => {
-    Alert.alert(labels.deleteDatabaseTitle, labels.deleteDatabaseExplainer, [
-      cancelButton,
-      { text: labels.deleteData, onPress: this.onDeleteData },
-    ])
-  }
-
-  onDeleteData = () => {
-    Alert.alert(labels.areYouSureTitle, labels.areYouSure, [
-      cancelButton,
-      {
-        text: labels.reallyDeleteData,
-        onPress: this.onDeleteDataConfirmation,
-      },
-    ])
-  }
-
-  onDeleteDataConfirmation = async () => {
-    await deleteDbAndOpenNew()
-    await saveEncryptionFlag(false)
-    this.props.enableShowApp()
-  }
-
-  passHashToDb = async (hash) => {
+const PasswordPrompt = ({ enableShowApp }) => {
+  const [password, setPassword] = useState(null)
+  const unlockApp = () => requestHash('check-pw', password)
+  const isPasswordEntered = Boolean(password)
+  const passHashToDb = async (hash) => {
     const connected = await openDb(hash)
+
     if (!connected) {
       Alert.alert(shared.incorrectPassword, shared.incorrectPasswordMessage, [
         {
           text: shared.tryAgain,
-          onPress: () => this.setState({ password: null }),
+          onPress: () => setPassword(null),
         },
       ])
       return
     }
-    this.props.enableShowApp()
+
+    enableShowApp()
   }
 
-  unlockApp = () => {
-    requestHash('check-pw', this.state.password)
+  useEffect(() => {
+    nodejs.channel.addListener('check-pw', passHashToDb, this)
+
+    return () => nodejs.channel.remove('check-pw', passHashToDb)
+  }, [])
+
+  const onDeleteDataConfirmation = async () => {
+    await deleteDbAndOpenNew()
+    await saveEncryptionFlag(false)
+    enableShowApp()
   }
 
-  setPassword = (password) => {
-    this.setState({ password })
+  const onDeleteData = () => {
+    Alert.alert(labels.areYouSureTitle, labels.areYouSure, [
+      cancelButton,
+      {
+        text: labels.reallyDeleteData,
+        onPress: onDeleteDataConfirmation,
+      },
+    ])
   }
 
-  render() {
-    const { password } = this.state
-    const isPasswordEntered = Boolean(password)
-
-    return (
-      <React.Fragment>
-        <Header isStatic />
-        <AppPage contentContainerStyle={styles.contentContainer}>
-          <AppTextInput
-            isKeyboardOffset={false}
-            onChangeText={this.setPassword}
-            secureTextEntry={true}
-            placeholder={labels.enterPassword}
-          />
-          <View style={styles.containerButtons}>
-            <Button onPress={this.onConfirmDeletion}>
-              {labels.forgotPassword}
-            </Button>
-            <Button
-              disabled={!isPasswordEntered}
-              isCTA={isPasswordEntered}
-              onPress={this.unlockApp}
-            >
-              {labels.title}
-            </Button>
-          </View>
-        </AppPage>
-      </React.Fragment>
-    )
+  const onConfirmDeletion = async () => {
+    Alert.alert(labels.deleteDatabaseTitle, labels.deleteDatabaseExplainer, [
+      cancelButton,
+      { text: labels.deleteData, onPress: onDeleteData },
+    ])
   }
+
+  return (
+    <>
+      <Header isStatic />
+      <AppPage contentContainerStyle={styles.contentContainer}>
+        <AppTextInput
+          isKeyboardOffset={false}
+          onChangeText={setPassword}
+          secureTextEntry={true}
+          placeholder={labels.enterPassword}
+        />
+        <View style={styles.containerButtons}>
+          <Button onPress={onConfirmDeletion}>{labels.forgotPassword}</Button>
+          <Button
+            disabled={!isPasswordEntered}
+            isCTA={isPasswordEntered}
+            onPress={unlockApp}
+          >
+            {labels.title}
+          </Button>
+        </View>
+      </AppPage>
+    </>
+  )
+}
+
+PasswordPrompt.propTypes = {
+  enableShowApp: PropTypes.func.isRequired,
 }
 
 const styles = StyleSheet.create({
@@ -119,3 +104,5 @@ const styles = StyleSheet.create({
     justifyContent: 'space-around',
   },
 })
+
+export default PasswordPrompt