diff --git a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt
index 040969e092..3d0dc4d80c 100644
--- a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt
+++ b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt
@@ -109,14 +109,17 @@ class TimelineItemContentMessageFactory @Inject constructor(
                 formattedFileSize = fileSizeFormatter.format(messageType.info?.size ?: 0),
                 fileExtension = fileExtensionExtractor.extractFromName(messageType.body)
             )
-            is FileMessageType -> TimelineItemFileContent(
-                body = messageType.body,
-                thumbnailSource = messageType.info?.thumbnailSource,
-                fileSource = messageType.source,
-                mimeType = messageType.info?.mimetype ?: MimeTypes.OctetStream,
-                formattedFileSize = fileSizeFormatter.format(messageType.info?.size ?: 0),
-                fileExtension = fileExtensionExtractor.extractFromName(messageType.body)
-            )
+            is FileMessageType -> {
+                val fileExtension = fileExtensionExtractor.extractFromName(messageType.body)
+                TimelineItemFileContent(
+                    body = messageType.body,
+                    thumbnailSource = messageType.info?.thumbnailSource,
+                    fileSource = messageType.source,
+                    mimeType = messageType.info?.mimetype ?: MimeTypes.fromFileExtension(fileExtension),
+                    formattedFileSize = fileSizeFormatter.format(messageType.info?.size ?: 0),
+                    fileExtension = fileExtension
+                )
+            }
             is NoticeMessageType -> TimelineItemNoticeContent(
                 body = messageType.body,
                 htmlDocument = messageType.formatted?.toHtmlDocument(),
diff --git a/libraries/core/src/main/kotlin/io/element/android/libraries/core/mimetype/MimeTypes.kt b/libraries/core/src/main/kotlin/io/element/android/libraries/core/mimetype/MimeTypes.kt
index c6373fbbf6..0506126568 100644
--- a/libraries/core/src/main/kotlin/io/element/android/libraries/core/mimetype/MimeTypes.kt
+++ b/libraries/core/src/main/kotlin/io/element/android/libraries/core/mimetype/MimeTypes.kt
@@ -51,4 +51,12 @@ object MimeTypes {
     fun String?.isMimeTypeFile() = this?.startsWith("file/").orFalse()
     fun String?.isMimeTypeText() = this?.startsWith("text/").orFalse()
     fun String?.isMimeTypeAny() = this?.startsWith("*/").orFalse()
+
+    fun fromFileExtension(fileExtension: String): String {
+        return when (fileExtension.lowercase()) {
+            "apk" -> Apk
+            "pdf" -> Pdf
+            else -> OctetStream
+        }
+    }
 }