diff --git a/requirements.txt b/requirements.txt
index 4c539ee..7356834 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ gevent==1.3.0
 APScheduler==3.6.0
 
 # Only use ujson with CPython (not PyPy)
-ujson==1.35
+ujson==5.4.0
 
 s3fs==0.4.0