diff --git a/ext/on-modify.timewarrior b/ext/on-modify.timewarrior
index 60c72237..ca65764b 100755
--- a/ext/on-modify.timewarrior
+++ b/ext/on-modify.timewarrior
@@ -39,8 +39,8 @@ import subprocess
 #   UDAs
 
 # Make no changes to the task, simply observe.
-old = json.loads(sys.stdin.readline())
-new = json.loads(sys.stdin.readline())
+old = json.loads(sys.stdin.buffer.readline().decode("utf-8", errors="replace"))
+new = json.loads(sys.stdin.buffer.readline().decode("utf-8", errors="replace"))
 print(json.dumps(new))
 
 def extract_timew_tags_from(json_obj):