diff --git a/taskcluster/fenix_taskgraph/release_promotion.py b/taskcluster/fenix_taskgraph/release_promotion.py
index a418720c4..c75a69b7c 100644
--- a/taskcluster/fenix_taskgraph/release_promotion.py
+++ b/taskcluster/fenix_taskgraph/release_promotion.py
@@ -171,4 +171,4 @@ def release_promotion_action(parameters, graph_config, input, task_group_id, tas
 
 def read_version_file():
     with open(os.path.join(os.path.dirname(__file__), '..', '..', 'version.txt')) as f:
-        return f.read().strip().decode('utf-8')
+        return f.read().strip()