diff --git a/requirements.txt b/requirements.txt
index 8e318bc05..538862aed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,6 +7,6 @@ thinc>=6.2.0,<6.3.0
 murmurhash>=0.26,<0.27
 plac<0.9.3
 six
-ujson
+ujson>=1.35
 cloudpickle
 sputnik>=0.9.2,<0.10.0
diff --git a/setup.py b/setup.py
index ef4e14020..70099da0a 100644
--- a/setup.py
+++ b/setup.py
@@ -234,7 +234,7 @@ def setup_package():
                 'cymem>=1.30,<1.32',
                 'preshed>=0.46.0,<0.47.0',
                 'thinc>=6.2.0,<6.3.0',
-                'plac',
+                'plac<0.9.3',
                 'six',
                 'cloudpickle',
                 'pathlib',