diff --git a/bump.py b/bump.py
index aacb299..5546948 100755
--- a/bump.py
+++ b/bump.py
@@ -2,7 +2,7 @@
 import sys
 
 def increment_version(actual_version, fragment):
-    if '~' in actual_version:
+    if '-' in actual_version:
         ver, pre = actual_version.split('-')
     else:
         ver = actual_version
@@ -48,6 +48,8 @@ def increment_version(actual_version, fragment):
     #remove the v prefix if any
     if actual_version.startswith('v'):
         actual_version = actual_version[1:]
+        
+    actual_version = actual_version.replace('~', '-')
 
     new_version = increment_version(actual_version, fragment)
     print(new_version)
diff --git a/test.sh b/test.sh
index 8f6fd15..694ee73 100755
--- a/test.sh
+++ b/test.sh
@@ -23,4 +23,5 @@ bump "1.0.0"
 bump "1.5.6"
 bump "4.2.0~dev.0"
 bump "1.0.0~dev.1"
-bump "1.0.0-rc.1"
\ No newline at end of file
+bump "1.0.0-rc.1"
+bump "1.4.1-dev.0"