diff --git a/pymzml/version.txt b/pymzml/version.txt
index ccbccc3d..c043eea7 100755
--- a/pymzml/version.txt
+++ b/pymzml/version.txt
@@ -1 +1 @@
-2.2.0
+2.2.1
diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index b8e32ae3..081c5529
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,7 @@
 numpy >= 1.8.0
 plotly < 2.0
 pynumpress >= 0.0.4
+regex
 
 # Testing and dev
 cython
@@ -9,5 +10,4 @@ coverage >= 4.2
 nose >= 1.3.7
 sphinx
 sphinx_rtd_theme
-regex
 
diff --git a/setup.py b/setup.py
index 46093ec5..4e4505d9 100755
--- a/setup.py
+++ b/setup.py
@@ -24,6 +24,7 @@
     python_requires  = '>=3.4.0',
     install_requires = [
         'numpy >= 1.8.0',
+        'regex'
     ],
     extras_require   = {
         'full': [