diff --git a/var/spack/repos/builtin/packages/py-widgetsnbextension/package.py b/var/spack/repos/builtin/packages/py-widgetsnbextension/package.py
index aa6dbb31c2..347641a8da 100644
--- a/var/spack/repos/builtin/packages/py-widgetsnbextension/package.py
+++ b/var/spack/repos/builtin/packages/py-widgetsnbextension/package.py
@@ -14,6 +14,7 @@ class PyWidgetsnbextension(PythonPackage):
 
     version('3.5.1', sha256='079f87d87270bce047512400efd70238820751a11d2d8cb137a5a5bdbaf255c7')
     version('3.4.2', sha256='fa618be8435447a017fd1bf2c7ae922d0428056cfc7449f7a8641edf76b48265')
+    version('3.4.0', sha256='c9d6e426a1d79d132b57b93b368feba2c66eb7b0fd34bdb901716b4b88e94497')
     version('3.3.0', sha256='c5280a62d293735cdadc7b8884e2affcfb0488420ee09963577f042359726392')
     version('1.2.6', sha256='c618cfb32978c9517caf0b4ef3aec312f8dd138577745e7b0d4abfcc7315ce51')