diff --git a/ReactNativeClient/android/gradle.properties b/ReactNativeClient/android/gradle.properties
index d541811d0..1a5d0b9d7 100644
--- a/ReactNativeClient/android/gradle.properties
+++ b/ReactNativeClient/android/gradle.properties
@@ -19,5 +19,5 @@
 
 # Required for react-native-webview
 # https://github.com/react-native-community/react-native-webview/blob/master/docs/Getting-Started.md
-# android.useAndroidX=true
-# android.enableJetifier=true
\ No newline at end of file
+android.useAndroidX=true
+android.enableJetifier=true
\ No newline at end of file
diff --git a/ReactNativeClient/lib/components/screens/config.js b/ReactNativeClient/lib/components/screens/config.js
index e5096b347..6dd34d799 100644
--- a/ReactNativeClient/lib/components/screens/config.js
+++ b/ReactNativeClient/lib/components/screens/config.js
@@ -1,5 +1,5 @@
 const React = require('react'); const Component = React.Component;
-const { Platform, TouchableOpacity, Linking, View, Switch, StyleSheet, Text, Button, ScrollView, TextInput } = require('react-native');
+const { Platform, TouchableOpacity, Linking, View, Switch, StyleSheet, Text, Button, ScrollView, TextInput, Alert } = require('react-native');
 const { connect } = require('react-redux');
 const { ScreenHeader } = require('lib/components/screen-header.js');
 const { _, setLocale } = require('lib/locale.js');
@@ -7,6 +7,7 @@ const { BaseScreenComponent } = require('lib/components/base-screen.js');
 const { Dropdown } = require('lib/components/Dropdown.js');
 const { themeStyle } = require('lib/components/global-style.js');
 const Setting = require('lib/models/Setting.js');
+const BaseItem = require('lib/models/BaseItem.js');
 const shared = require('lib/components/shared/config-shared.js');
 const SyncTargetRegistry = require('lib/SyncTargetRegistry');
 const { reg } = require('lib/registry.js');
@@ -33,6 +34,35 @@ class ConfigScreenComponent extends BaseScreenComponent {
 		this.saveButton_press = () => {
 			return shared.saveSettings(this);
 		};
+
+		this.clearSyncStateButton_click = () => {
+			Alert.alert(
+				'',
+				_('WARNING: This will clear the local synchronisation state. It means the entire data will be synced again with the sync target. DO NOT USE if you have not been advised to do so, or if you do not understand the consequences.'),
+				[
+					{
+						text: _('Help'),
+						onPress: () => {
+							Linking.openURL('https://joplinapp.org/faq/#how-to-clear-local-sync-data');
+						},
+					},
+					{
+						text: _('Cancel'),
+						onPress: () => {},
+						style: 'cancel',
+					},
+					{
+						text: _('OK'),
+						onPress: async () => {
+							const syncTarget = this.props.settings['sync.target'];
+							await BaseItem.clearLocalSyncState(syncTarget);
+							alert(_('The local sync data has been cleared.'));
+						},
+					},
+				],
+				{ cancelable: false },
+			);
+		};
 	}
 
 	UNSAFE_componentWillMount() {
@@ -273,6 +303,18 @@ class ConfigScreenComponent extends BaseScreenComponent {
 
 		const settingComps = shared.settingsToComponents2(this, 'mobile', settings);
 
+		settingComps.push(this.renderHeader('advanced', _('Advanced')));
+
+		settingComps.push(
+			<View key="advanced_clear_sync_state" style={this.styles().settingContainer}>
+				<View style={{flex:1, flexDirection: 'column'}}>
+					<View style={{flex:1}}>
+						<Button title={_('Clear synchronisation state')} onPress={this.clearSyncStateButton_click}/>
+					</View>
+				</View>
+			</View>
+		);
+
 		settingComps.push(this.renderHeader('moreInfo', _('More information')));
 
 		if (Platform.OS === 'android' && Platform.Version >= 23) {
diff --git a/ReactNativeClient/lib/models/BaseItem.js b/ReactNativeClient/lib/models/BaseItem.js
index 5fd542af4..e58a34cbc 100644
--- a/ReactNativeClient/lib/models/BaseItem.js
+++ b/ReactNativeClient/lib/models/BaseItem.js
@@ -694,6 +694,11 @@ class BaseItem extends BaseModel {
 		}
 	}
 
+	static async clearLocalSyncState(syncTarget) {
+		await this.db().exec('DELETE FROM sync_items WHERE sync_target = ?', [syncTarget]);
+		await this.db().exec('DELETE FROM deleted_items WHERE sync_target = ?', [syncTarget]);
+	}
+
 	static async forceSync(itemId) {
 		await this.db().exec('UPDATE sync_items SET force_sync = 1 WHERE item_id = ?', [itemId]);
 	}