diff --git a/= b/=
deleted file mode 100644
index e69de29..0000000
diff --git a/requirements.txt b/requirements.txt
index ce36008..9a94f0c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,15 +1,16 @@
-lxml >= 3.6.0, < 3.7
+lxml >= 3.5.0, < 4
 nose
 mock
 coveralls
+http://xmlsoft.org/sources/python/libxml2-python-2.6.21.tar.gz
 https://github.com/odoo-brazil/pyxmlsec/archive/master.zip
 Jinja2
 signxml
 suds >= 0.4
 suds_requests >= 0.3
-defusedxml >= 0.4.1, < 0.5
-eight >= 0.3.0, < 0.4
-cryptography >= 1.4, < 1.8
+defusedxml >= 0.4.1, < 0.6
+eight >= 0.3.0, < 0.5
+cryptography >= 1.8, < 1.10
 pyOpenSSL >= 16.0.0, < 17
 certifi >= 2015.11.20.1
 reportlab
diff --git a/setup.py b/setup.py
index cba8e5c..b1e6f1a 100644
--- a/setup.py
+++ b/setup.py
@@ -35,8 +35,8 @@ later (LGPLv2+)',
     long_description=open('README.md', 'r').read(),
     install_requires=[
         'Jinja2 >= 2.8',
-        'signxml == 2.2.6',
-        'lxml >= 3.6.0, < 3.7',
+        'signxml >= 2.4.0',
+        'lxml >= 3.5.0, < 4',
         'suds >= 0.4',
         'suds_requests >= 0.3',
         'reportlab'