diff --git a/data/requirements.txt b/data/requirements.txt
index 1a03352b56..8a163d4c7e 100644
--- a/data/requirements.txt
+++ b/data/requirements.txt
@@ -3,4 +3,4 @@ numpy>=1.9,!=1.16.0; sys_platform == 'win32'
 pyqt5; sys_platform != 'win32'
 pyqt5!=5.14.2; sys_platform == 'win32'
 psutil
-cython
+cython!=0.29.18
diff --git a/src/urh/signalprocessing/Encoding.py b/src/urh/signalprocessing/Encoding.py
index 03e80aec70..8a82b8ce18 100755
--- a/src/urh/signalprocessing/Encoding.py
+++ b/src/urh/signalprocessing/Encoding.py
@@ -74,10 +74,6 @@ def name(self):
     def is_nrz(self) -> bool:
         return len(self.chain) <= 1
 
-    @property
-    def is_nrzi(self) -> bool:
-        return len(self.chain) == 2 and self.chain[1] == self.code_differential
-
     @property
     def contains_cut(self) -> bool:
         return self.code_cut in self.chain
diff --git a/src/urh/util/ProjectManager.py b/src/urh/util/ProjectManager.py
index 27a8cad3c3..5a33747ff9 100644
--- a/src/urh/util/ProjectManager.py
+++ b/src/urh/util/ProjectManager.py
@@ -122,8 +122,8 @@ def load_decodings(self):
 
         fallback = [Encoding(["Non Return To Zero (NRZ)"]),
 
-                    Encoding(["Non Return To Zero Inverted (NRZ-I)",
-                              settings.DECODING_DIFFERENTIAL]),
+                    Encoding(["Non Return To Zero + Invert",
+                              settings.DECODING_INVERT]),
 
                     Encoding(["Manchester I",
                               settings.DECODING_EDGE]),