diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e855aed..a26713a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## [0.3.5] - 28nd Aug 2021
+- hotfix: Send unencrypted thumbnails
+
 ## [0.3.4] - 28nd Aug 2021
 - fix: String.parseIdentifierIntoParts not working with unicode matrix.to links
     Some clients do not uri-encode the identifier for matrix.to links, so we must
diff --git a/lib/src/room.dart b/lib/src/room.dart
index cf03db34..1b940d35 100644
--- a/lib/src/room.dart
+++ b/lib/src/room.dart
@@ -689,7 +689,7 @@ class Room {
       'info': {
         ...file.info,
         if (thumbnail != null && encryptedThumbnail == null)
-          'thumbnail_url': thumbnailUploadResp,
+          'thumbnail_url': thumbnailUploadResp.toString(),
         if (thumbnail != null && encryptedThumbnail != null)
           'thumbnail_file': {
             'url': thumbnailUploadResp.toString(),
diff --git a/pubspec.yaml b/pubspec.yaml
index 90a29b1b..02f2a6e2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: matrix
 description: Matrix Dart SDK
-version: 0.3.4
+version: 0.3.5
 homepage: https://famedly.com
 
 environment: