diff --git a/pytrustnfe/nfe/__init__.py b/pytrustnfe/nfe/__init__.py
index 72786b7..9a0d068 100644
--- a/pytrustnfe/nfe/__init__.py
+++ b/pytrustnfe/nfe/__init__.py
@@ -134,7 +134,7 @@ def _send(certificado, method, **kwargs):
 
     port = next(iter(client.wsdl.port_types))
     first_operation = [x for x in iter(
-        client.wsdl.port_types[port].operations) if "Zip" not in x][0]
+        client.wsdl.port_types[port].operations) if "zip" not in x.lower()][0]
 
     namespaceNFe = xml.find(".//{http://www.portalfiscal.inf.br/nfe}NFe")
     if namespaceNFe is not None:
diff --git a/setup.py b/setup.py
index 97e5aa1..e0c8dde 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup, find_packages
 
 
-VERSION = "1.0.3"
+VERSION = "1.0.4"
 
 
 setup(