diff --git a/src/function/sync/get-server-data-status/campaign.ts b/src/function/sync/get-server-data-status/campaign.ts
new file mode 100644
index 0000000..f32f508
--- /dev/null
+++ b/src/function/sync/get-server-data-status/campaign.ts
@@ -0,0 +1,64 @@
+/*
+ * server component for the TimeLimit App
+ * Copyright (C) 2019 - 2026 Jonas Lochmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import { createHash } from 'crypto'
+
+const updateMessage =
+  'Please update the TimeLimit App to the latest release. ' +
+  'In your current version, synchronization and purchases may not work as expected.' +
+  '\n\n' +
+  'Bitte die TimeLimit-App aktualisieren. ' +
+  'Mit der momentan installierten Version kann es zu Einschränkungen bei der Synchronisation und bei Käufen kommen.'
+
+export function getCampaign({ familyId, isClient750OrNewer }: {
+  familyId: string
+  isClient750OrNewer: boolean
+}): string | undefined {
+  const now = Date.now()
+
+  const campaigns = [
+    {
+      enable: !isClient750OrNewer,
+      seed: 'Q05NwM4nyUfiYg6K', // require('crypto').randomBytes(12).toString('base64')
+      startTime: 1784160000000, // new Date('2026-07-16').valueOf()
+      endTime: 1785369600000, // new Date('2026-07-30').valueOf()
+      startPercentage: 0,
+      endPercentage: 10,
+      message: updateMessage,
+    }
+  ]
+
+  for (const campaign of campaigns) {
+    if (!campaign.enable) continue
+    if (now < campaign.startTime) continue
+
+    const progress = Math.min((now - campaign.startTime) / (campaign.endTime - campaign.startTime), 1)
+    const chanceInPercent = campaign.startPercentage + progress * (campaign.endPercentage - campaign.startPercentage)
+
+    const hasher = createHash('SHA3-224')
+
+    hasher.update(campaign.seed, 'base64')
+    hasher.update(familyId)
+
+    const hash = hasher.digest().readUInt32BE(0)
+    const match = hash < chanceInPercent * Math.pow(2, 32) / 100
+
+    if (match) return campaign.message
+  }
+
+  return undefined
+}
diff --git a/src/function/sync/get-server-data-status/index.ts b/src/function/sync/get-server-data-status/index.ts
index 6eb391e..7d54575 100644
--- a/src/function/sync/get-server-data-status/index.ts
+++ b/src/function/sync/get-server-data-status/index.ts
@@ -22,6 +22,7 @@ import { getStatusMessage } from '../../../function/statusmessage'
 import { ClientDataStatus } from '../../../object/clientdatastatus'
 import { ServerDataStatus } from '../../../object/serverdatastatus'
 import { EventHandler } from '../../../monitoring/eventhandler'
+import { getCampaign } from './campaign'
 import {
   getCategoryAssignedApps, getCategoryBaseDatas, getCategoryDataToSync,
   getRules, getTasks, getUsedTimes
@@ -54,12 +55,18 @@ export const generateServerDataStatus = async ({
   const doesClientSupportDh = clientLevel >= 5
   const doesClientSupportU2f = clientLevel >= 6
   const doesClientSupportPing = clientLevel >= 7
+  const isClient750OrNewer = clientLevel >= 8 // first release in the post gplay time
+
+  const message: string | undefined =
+    await getStatusMessage({ database, transaction }) ||
+    getCampaign({ familyId, isClient750OrNewer }) ||
+    undefined
 
   const result: ServerDataStatus = {
     fullVersion: config.alwaysPro ? 1 : (
       familyEntry.hasFullVersion ? parseInt(familyEntry.fullVersionUntil, 10) : 0
     ),
-    message: await getStatusMessage({ database, transaction }) || undefined,
+    message,
     apiLevel: 9
   }