diff --git a/build.gradle.kts b/build.gradle.kts
index c0a91ee..89a6136 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -63,7 +63,7 @@ version = "0.0.0" // Automatically overwritten by CI
 // Versions of dependencies
 extra["slf4jVersion"] = "2.0.7"
 // FIXME: Check if we can remove this after we port the new auth from android-backend to this library
-extra["cyfaceSerializationVersion"] = "3.2.0-alpha1"
+extra["cyfaceSerializationVersion"] = "3.2.0-alpha2"
 extra["googleApiClientVersion"] = "2.2.0" // transmission protocol
 extra["gradleWrapperVersion"] = "7.6.1"
 
diff --git a/src/main/kotlin/de/cyface/uploader/DefaultUploader.kt b/src/main/kotlin/de/cyface/uploader/DefaultUploader.kt
index 9d4e775..7f76d33 100644
--- a/src/main/kotlin/de/cyface/uploader/DefaultUploader.kt
+++ b/src/main/kotlin/de/cyface/uploader/DefaultUploader.kt
@@ -393,6 +393,7 @@ class DefaultUploader(private val apiEndpoint: String) : Uploader {
             attributes["logCount"] = metaData.logCount.toString()
             attributes["imageCount"] = metaData.imageCount.toString()
             attributes["videoCount"] = metaData.videoCount.toString()
+            attributes["filesSize"] = metaData.filesSize.toString()
             return attributes
         }
 
diff --git a/src/main/kotlin/de/cyface/uploader/RequestInitializeHandler.kt b/src/main/kotlin/de/cyface/uploader/RequestInitializeHandler.kt
index 12fea6f..05069d0 100644
--- a/src/main/kotlin/de/cyface/uploader/RequestInitializeHandler.kt
+++ b/src/main/kotlin/de/cyface/uploader/RequestInitializeHandler.kt
@@ -75,5 +75,6 @@ class RequestInitializeHandler(
         headers["logCount"] = metaData.logCount
         headers["imageCount"] = metaData.imageCount
         headers["videoCount"] = metaData.videoCount
+        headers["filesSize"] = metaData.filesSize
     }
 }