diff --git a/client/src/app/app.component.ts b/client/src/app/app.component.ts
index 7c99755db..f0e6dc613 100644
--- a/client/src/app/app.component.ts
+++ b/client/src/app/app.component.ts
@@ -4,13 +4,14 @@ import { TranslateService } from '@ngx-translate/core';
 import { take, filter } from 'rxjs/operators';
 
 import { ConfigService } from './core/ui-services/config.service';
-import { ConstantsService } from './core/ui-services/constants.service';
+import { ConstantsService } from './core/core-services/constants.service';
 import { CountUsersService } from './core/ui-services/count-users.service';
 import { LoadFontService } from './core/ui-services/load-font.service';
 import { LoginDataService } from './core/ui-services/login-data.service';
 import { OperatorService } from './core/core-services/operator.service';
 import { ServertimeService } from './core/core-services/servertime.service';
 import { ThemeService } from './core/ui-services/theme.service';
+import { DataStoreUpgradeService } from './core/core-services/data-store-upgrade.service';
 
 /**
  * Angular's global App Component
@@ -48,7 +49,8 @@ export class AppComponent {
         themeService: ThemeService,
         countUsersService: CountUsersService, // Needed to register itself.
         configService: ConfigService,
-        loadFontService: LoadFontService
+        loadFontService: LoadFontService,
+        dataStoreUpgradeService: DataStoreUpgradeService // to start it.
     ) {
         // manually add the supported languages
         translate.addLangs(['en', 'de', 'cs']);
diff --git a/client/src/app/core/core-services/autoupdate.service.ts b/client/src/app/core/core-services/autoupdate.service.ts
index c771352dc..68d5728fd 100644
--- a/client/src/app/core/core-services/autoupdate.service.ts
+++ b/client/src/app/core/core-services/autoupdate.service.ts
@@ -145,4 +145,22 @@ export class AutoupdateService {
         console.log('requesting changed objects with DS max change id', this.DS.maxChangeId + 1);
         this.websocketService.send('getElements', { change_id: this.DS.maxChangeId + 1 });
     }
+
+    /**
+     * Does a full update: Requests all data from the server and sets the DS to the fresh data.
+     */
+    public async doFullUpdate(): Promise<void> {
+        const response = await this.websocketService.sendAndGetResponse<{}, AutoupdateFormat>('getElements', {});
+
+        let allModels: BaseModel[] = [];
+        for (const collection of Object.keys(response.changed)) {
+            if (this.modelMapper.isCollectionRegistered(collection)) {
+                allModels = allModels.concat(this.mapObjectsToBaseModels(collection, response.changed[collection]));
+            } else {
+                console.error(`Unregistered collection "${collection}". Ignore it.`);
+            }
+        }
+
+        await this.DS.set(allModels, response.to_change_id);
+    }
 }
diff --git a/client/src/app/core/ui-services/constants.service.spec.ts b/client/src/app/core/core-services/constants.service.spec.ts
similarity index 100%
rename from client/src/app/core/ui-services/constants.service.spec.ts
rename to client/src/app/core/core-services/constants.service.spec.ts
diff --git a/client/src/app/core/ui-services/constants.service.ts b/client/src/app/core/core-services/constants.service.ts
similarity index 94%
rename from client/src/app/core/ui-services/constants.service.ts
rename to client/src/app/core/core-services/constants.service.ts
index e4a0cc61f..3d4c507ad 100644
--- a/client/src/app/core/ui-services/constants.service.ts
+++ b/client/src/app/core/core-services/constants.service.ts
@@ -1,6 +1,6 @@
 import { Injectable } from '@angular/core';
 
-import { WebsocketService } from '../core-services/websocket.service';
+import { WebsocketService } from './websocket.service';
 import { Observable, of, Subject } from 'rxjs';
 
 /**
@@ -15,7 +15,7 @@ interface Constants {
  *
  * @example
  * ```ts
- * this.constantsService.get('OpenSlidesSettings').subscribe(constant => {
+ * this.constantsService.get('Settings').subscribe(constant => {
  *     console.log(constant);
  * });
  * ```
diff --git a/client/src/app/core/core-services/data-store-upgrade.service.spec.ts b/client/src/app/core/core-services/data-store-upgrade.service.spec.ts
new file mode 100644
index 000000000..091233bfb
--- /dev/null
+++ b/client/src/app/core/core-services/data-store-upgrade.service.spec.ts
@@ -0,0 +1,17 @@
+import { TestBed, inject } from '@angular/core/testing';
+
+import { E2EImportsModule } from '../../../e2e-imports.module';
+import { DataStoreUpgradeService } from './data-store-upgrade.service';
+
+describe('DataStoreUpgradeService', () => {
+    beforeEach(() => {
+        TestBed.configureTestingModule({
+            imports: [E2EImportsModule],
+            providers: [DataStoreUpgradeService]
+        });
+    });
+
+    it('should be created', inject([DataStoreUpgradeService], (service: DataStoreUpgradeService) => {
+        expect(service).toBeTruthy();
+    }));
+});
diff --git a/client/src/app/core/core-services/data-store-upgrade.service.ts b/client/src/app/core/core-services/data-store-upgrade.service.ts
new file mode 100644
index 000000000..743b76971
--- /dev/null
+++ b/client/src/app/core/core-services/data-store-upgrade.service.ts
@@ -0,0 +1,34 @@
+import { Injectable } from '@angular/core';
+
+import { ConstantsService } from './constants.service';
+import { AutoupdateService } from './autoupdate.service';
+import { StorageService } from './storage.service';
+
+const MIGRATIONVERSION = 'MigrationVersion';
+
+/**
+ * Manages upgrading the DataStore, if the migration version from the server is higher than the current one.
+ */
+@Injectable({
+    providedIn: 'root'
+})
+export class DataStoreUpgradeService {
+    /**
+     * @param autoupdateService
+     * @param constantsService
+     * @param storageService
+     */
+    public constructor(
+        autoupdateService: AutoupdateService,
+        constantsService: ConstantsService,
+        storageService: StorageService
+    ) {
+        constantsService.get<number>(MIGRATIONVERSION).subscribe(async version => {
+            const currentVersion = await storageService.get<number>(MIGRATIONVERSION);
+            await storageService.set(MIGRATIONVERSION, version);
+            if (currentVersion && currentVersion !== version) {
+                autoupdateService.doFullUpdate();
+            }
+        });
+    }
+}
diff --git a/client/src/app/core/core-services/websocket.service.ts b/client/src/app/core/core-services/websocket.service.ts
index 85a31d43e..03cbfd625 100644
--- a/client/src/app/core/core-services/websocket.service.ts
+++ b/client/src/app/core/core-services/websocket.service.ts
@@ -10,12 +10,26 @@ import { formatQueryParams, QueryParams } from '../query-params';
 /**
  * The generic message format in which messages are send and recieved by the server.
  */
-interface WebsocketMessage {
+interface BaseWebsocketMessage {
     type: string;
     content: any;
+}
+
+/**
+ * Outgoing messages must have an id.
+ */
+interface OutgoingWebsocketMessage extends BaseWebsocketMessage {
     id: string;
 }
 
+/**
+ * Incomming messages may have an `in_response`, if they are an answer to a previously
+ * submitted request.
+ */
+interface IncommingWebsocketMessage extends BaseWebsocketMessage {
+    in_response?: string;
+}
+
 /**
  * Service that handles WebSocket connections. Other services can register themselfs
  * with {@method getOberservable} for a specific type of messages. The content will be published.
@@ -89,6 +103,8 @@ export class WebsocketService {
      */
     private subjects: { [type: string]: Subject<any> } = {};
 
+    private responseCallbacks: { [id: string]: [(val: any) => boolean, (error: string) => void | null] } = {};
+
     /**
      * Saves, if the WS Connection should be closed (e.g. after an explicit `close()`). Prohibits
      * retry connection attempts.
@@ -180,16 +196,7 @@ export class WebsocketService {
 
         this.websocket.onmessage = (event: MessageEvent) => {
             this.zone.run(() => {
-                const message: WebsocketMessage = JSON.parse(event.data);
-                const type: string = message.type;
-                if (type === 'error') {
-                    console.error('Websocket error', message.content);
-                } else if (this.subjects[type]) {
-                    // Pass the content to the registered subscribers.
-                    this.subjects[type].next(message.content);
-                } else {
-                    console.log(`Got unknown websocket message type "${type}" with content`, message.content);
-                }
+                this.handleMessage(event.data);
             });
         };
 
@@ -234,6 +241,48 @@ export class WebsocketService {
         };
     }
 
+    /**
+     * Handles an incomming message.
+     *
+     * @param data The message
+     */
+    private handleMessage(data: string): void {
+        const message: IncommingWebsocketMessage = JSON.parse(data);
+        const type = message.type;
+        const inResponse = message.in_response;
+        const callbacks = this.responseCallbacks[inResponse];
+        if (callbacks) {
+            delete this.responseCallbacks[inResponse];
+        }
+
+        if (type === 'error') {
+            console.error('Websocket error', message.content);
+            if (inResponse && callbacks && callbacks[1]) {
+                callbacks[1](message.content as string);
+            }
+            return;
+        }
+
+        // Try to fire a response callback directly. If it returnes true, the message is handeled
+        // and not distributed further
+        if (inResponse && callbacks && callbacks[0](message.content)) {
+            return;
+        }
+
+        if (this.subjects[type]) {
+            // Pass the content to the registered subscribers.
+            this.subjects[type].next(message.content);
+        } else {
+            console.warn(
+                `Got unknown websocket message type "${type}" (inResponse: ${inResponse}) with content`,
+                message.content
+            );
+        }
+    }
+
+    /**
+     * Closes the connection error notice
+     */
     private dismissConnectionErrorNotice(): void {
         if (this.connectionErrorNotice) {
             this.connectionErrorNotice.dismiss();
@@ -269,13 +318,23 @@ export class WebsocketService {
      *
      * @param type the message type
      * @param content the actual content
+     * @param success an optional success callback for a response
+     * @param error an optional error callback for a response
+     * @param id an optional id for the message. If not given, a random id will be generated and returned.
+     * @returns the message id
      */
-    public send<T>(type: string, content: T, id?: string): void {
+    public send<T, R>(
+        type: string,
+        content: T,
+        success?: (val: R) => boolean,
+        error?: (error: string) => void,
+        id?: string
+    ): string {
         if (!this.websocket) {
             return;
         }
 
-        const message: WebsocketMessage = {
+        const message: OutgoingWebsocketMessage = {
             type: type,
             content: content,
             id: id
@@ -290,6 +349,10 @@ export class WebsocketService {
             }
         }
 
+        if (success) {
+            this.responseCallbacks[message.id] = [success, error];
+        }
+
         // Either send directly or add to queue, if not connected.
         const jsonMessage = JSON.stringify(message);
         if (this.isConnected) {
@@ -297,5 +360,29 @@ export class WebsocketService {
         } else {
             this.sendQueueWhileNotConnected.push(jsonMessage);
         }
+
+        return message.id;
+    }
+
+    /**
+     * Sends a message and waits for the response
+     *
+     * @param type the message type
+     * @param content the actual content
+     * @param id an optional id for the message. If not given, a random id will be generated and returned.
+     */
+    public sendAndGetResponse<T, R>(type: string, content: T, id?: string): Promise<R> {
+        return new Promise<R>((resolve, reject) => {
+            this.send<T, R>(
+                type,
+                content,
+                val => {
+                    resolve(val);
+                    return true;
+                },
+                reject,
+                id
+            );
+        });
     }
 }
diff --git a/client/src/app/core/repositories/config/config-repository.service.ts b/client/src/app/core/repositories/config/config-repository.service.ts
index f92c3a96a..f0a495f06 100644
--- a/client/src/app/core/repositories/config/config-repository.service.ts
+++ b/client/src/app/core/repositories/config/config-repository.service.ts
@@ -1,18 +1,18 @@
 import { Injectable } from '@angular/core';
 
 import { Observable, BehaviorSubject } from 'rxjs';
+import { TranslateService } from '@ngx-translate/core';
 
 import { BaseRepository } from 'app/core/repositories/base-repository';
 import { Config } from 'app/shared/models/core/config';
 import { DataSendService } from 'app/core/core-services/data-send.service';
 import { DataStoreService } from 'app/core/core-services/data-store.service';
-import { ConstantsService } from 'app/core/ui-services/constants.service';
+import { ConstantsService } from 'app/core/core-services/constants.service';
 import { HttpService } from 'app/core/core-services/http.service';
 import { Identifiable } from 'app/shared/models/base/identifiable';
 import { CollectionStringMapperService } from 'app/core/core-services/collectionStringMapper.service';
 import { ViewModelStoreService } from 'app/core/core-services/view-model-store.service';
 import { ViewConfig } from 'app/site/config/models/view-config';
-import { TranslateService } from '@ngx-translate/core';
 
 /**
  * Holds a single config item.
@@ -107,7 +107,7 @@ export class ConfigRepositoryService extends BaseRepository<ViewConfig, Config>
     ) {
         super(DS, dataSend, mapperService, viewModelStoreService, translate, Config);
 
-        this.constantsService.get('OpenSlidesConfigVariables').subscribe(constant => {
+        this.constantsService.get('ConfigVariables').subscribe(constant => {
             this.createConfigStructure(constant);
             this.updateConfigStructure(...Object.values(this.viewModelStore));
             this.updateConfigListObservable();
diff --git a/client/src/app/core/repositories/users/group-repository.service.ts b/client/src/app/core/repositories/users/group-repository.service.ts
index ee02196ad..a40a7c621 100644
--- a/client/src/app/core/repositories/users/group-repository.service.ts
+++ b/client/src/app/core/repositories/users/group-repository.service.ts
@@ -2,7 +2,7 @@ import { Injectable } from '@angular/core';
 
 import { BaseRepository } from '../base-repository';
 import { CollectionStringMapperService } from '../../core-services/collectionStringMapper.service';
-import { ConstantsService } from '../../ui-services/constants.service';
+import { ConstantsService } from '../../core-services/constants.service';
 import { DataSendService } from '../../core-services/data-send.service';
 import { DataStoreService } from '../../core-services/data-store.service';
 import { Group } from 'app/shared/models/users/group';
diff --git a/client/src/app/core/ui-services/config.service.ts b/client/src/app/core/ui-services/config.service.ts
index c3cb275e3..c3da2a131 100644
--- a/client/src/app/core/ui-services/config.service.ts
+++ b/client/src/app/core/ui-services/config.service.ts
@@ -1,6 +1,7 @@
 import { Injectable } from '@angular/core';
 
 import { Observable, BehaviorSubject } from 'rxjs';
+
 import { Config } from '../../shared/models/core/config';
 import { DataStoreService } from '../core-services/data-store.service';
 
diff --git a/client/src/app/shared/models/agenda/item.ts b/client/src/app/shared/models/agenda/item.ts
index 5c2e2b647..5f1f8a8e4 100644
--- a/client/src/app/shared/models/agenda/item.ts
+++ b/client/src/app/shared/models/agenda/item.ts
@@ -12,7 +12,7 @@ interface ContentObject {
 
 /**
  * Determine visibility states for agenda items
- * Coming from "OpenSlidesConfigVariables" property "agenda_hide_internal_items_on_projector"
+ * Coming from "ConfigVariables" property "agenda_hide_internal_items_on_projector"
  */
 export const itemVisibilityChoices = [
     { key: 1, name: 'Public item', csvName: '' },
diff --git a/client/src/app/site/assignments/components/assignment-detail/assignment-detail.component.ts b/client/src/app/site/assignments/components/assignment-detail/assignment-detail.component.ts
index 00d654c2b..b3503d034 100644
--- a/client/src/app/site/assignments/components/assignment-detail/assignment-detail.component.ts
+++ b/client/src/app/site/assignments/components/assignment-detail/assignment-detail.component.ts
@@ -11,7 +11,7 @@ import { Assignment } from 'app/shared/models/assignments/assignment';
 import { AssignmentPollService } from '../../services/assignment-poll.service';
 import { AssignmentRepositoryService } from 'app/core/repositories/assignments/assignment-repository.service';
 import { BaseViewComponent } from 'app/site/base/base-view';
-import { ConstantsService } from 'app/core/ui-services/constants.service';
+import { ConstantsService } from 'app/core/core-services/constants.service';
 import { ItemRepositoryService } from 'app/core/repositories/agenda/item-repository.service';
 import { LocalPermissionsService } from 'app/site/motions/services/local-permissions.service';
 import { OperatorService } from 'app/core/core-services/operator.service';
diff --git a/client/src/app/site/assignments/services/assignment-filter.service.ts b/client/src/app/site/assignments/services/assignment-filter.service.ts
index 78e0d212d..1051ce19a 100644
--- a/client/src/app/site/assignments/services/assignment-filter.service.ts
+++ b/client/src/app/site/assignments/services/assignment-filter.service.ts
@@ -5,7 +5,7 @@ import { Assignment } from 'app/shared/models/assignments/assignment';
 import { BaseFilterListService, OsFilter } from 'app/core/ui-services/base-filter-list.service';
 import { StorageService } from 'app/core/core-services/storage.service';
 import { ViewAssignment, AssignmentPhase } from '../models/view-assignment';
-import { ConstantsService } from 'app/core/ui-services/constants.service';
+import { ConstantsService } from 'app/core/core-services/constants.service';
 
 @Injectable({
     providedIn: 'root'
diff --git a/client/src/app/site/motions/modules/motion-detail/components/motion-poll/motion-poll.component.ts b/client/src/app/site/motions/modules/motion-detail/components/motion-poll/motion-poll.component.ts
index 856bc5101..d62c0114f 100644
--- a/client/src/app/site/motions/modules/motion-detail/components/motion-poll/motion-poll.component.ts
+++ b/client/src/app/site/motions/modules/motion-detail/components/motion-poll/motion-poll.component.ts
@@ -4,7 +4,7 @@ import { MatDialog } from '@angular/material';
 import { TranslateService } from '@ngx-translate/core';
 
 import { CalculablePollKey } from 'app/core/ui-services/poll.service';
-import { ConstantsService } from 'app/core/ui-services/constants.service';
+import { ConstantsService } from 'app/core/core-services/constants.service';
 import { LocalPermissionsService } from 'app/site/motions/services/local-permissions.service';
 import { MotionPoll } from 'app/shared/models/motions/motion-poll';
 import { MotionPollDialogComponent } from './motion-poll-dialog.component';
@@ -209,7 +209,7 @@ export class MotionPollComponent implements OnInit {
      * Subscribe to the available majority choices as given in the server-side constants
      */
     private subscribeMajorityChoices(): void {
-        this.constants.get<any>('OpenSlidesConfigVariables').subscribe(constants => {
+        this.constants.get<any>('ConfigVariables').subscribe(constants => {
             const motionconst = constants.find(c => c.name === 'Motions');
             if (motionconst) {
                 const ballotConst = motionconst.subgroups.find(s => s.name === 'Voting and ballot papers');
diff --git a/client/src/app/site/motions/services/local-permissions.service.ts b/client/src/app/site/motions/services/local-permissions.service.ts
index b41ca247b..341ec5620 100644
--- a/client/src/app/site/motions/services/local-permissions.service.ts
+++ b/client/src/app/site/motions/services/local-permissions.service.ts
@@ -3,9 +3,9 @@ import { Injectable } from '@angular/core';
 import { OperatorService } from 'app/core/core-services/operator.service';
 import { ViewMotion } from '../models/view-motion';
 import { ConfigService } from 'app/core/ui-services/config.service';
-import { ConstantsService } from 'app/core/ui-services/constants.service';
+import { ConstantsService } from 'app/core/core-services/constants.service';
 
-interface OpenSlidesSettings {
+interface Settings {
     MOTIONS_ALLOW_AMENDMENTS_OF_AMENDMENTS: boolean;
 }
 
@@ -30,7 +30,7 @@ export class LocalPermissionsService {
             .get<boolean>('motions_amendments_enabled')
             .subscribe(enabled => (this.amendmentEnabled = enabled));
         this.constants
-            .get<OpenSlidesSettings>('OpenSlidesSettings')
+            .get<Settings>('Settings')
             .subscribe(settings => (this.amendmentOfAmendment = settings.MOTIONS_ALLOW_AMENDMENTS_OF_AMENDMENTS));
     }
 
diff --git a/openslides/core/apps.py b/openslides/core/apps.py
index f1d51b1b1..b8a38f592 100644
--- a/openslides/core/apps.py
+++ b/openslides/core/apps.py
@@ -6,6 +6,7 @@ from typing import Any, Dict, List, Set
 
 from django.apps import AppConfig
 from django.conf import settings
+from django.db.models import Max
 from django.db.models.signals import post_migrate, pre_delete
 
 
@@ -155,7 +156,7 @@ class CoreAppConfig(AppConfig):
                 # Settings key does not exist. Do nothing. The client will
                 # treat this as undefined.
                 pass
-        constants["OpenSlidesSettings"] = client_settings_dict
+        constants["Settings"] = client_settings_dict
 
         # Config variables
         config_groups: List[Any] = []
@@ -181,7 +182,14 @@ class CoreAppConfig(AppConfig):
                 )
             # Add the config variable to the current group and subgroup.
             config_groups[-1]["subgroups"][-1]["items"].append(config_variable.data)
-        constants["OpenSlidesConfigVariables"] = config_groups
+        constants["ConfigVariables"] = config_groups
+
+        # get max migration id -> the "version" of the DB
+        from django.db.migrations.recorder import MigrationRecorder
+
+        constants["MigrationVersion"] = MigrationRecorder.Migration.objects.aggregate(
+            Max("id")
+        )["id__max"]
 
         return constants