diff --git a/Lib/fontTools/__init__.py b/Lib/fontTools/__init__.py
index 2246764f0..12d0278f6 100644
--- a/Lib/fontTools/__init__.py
+++ b/Lib/fontTools/__init__.py
@@ -4,6 +4,6 @@ from fontTools.misc.loggingTools import configLogger
 
 log = logging.getLogger(__name__)
 
-version = __version__ = "4.5.0"
+version = __version__ = "4.5.1.dev0"
 
 __all__ = ["version", "log", "configLogger"]
diff --git a/setup.cfg b/setup.cfg
index 3f2e3311e..0478e2fbb 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 4.5.0
+current_version = 4.5.1.dev0
 commit = True
 tag = False
 tag_name = {new_version}
diff --git a/setup.py b/setup.py
index 61157407c..e9ee72333 100755
--- a/setup.py
+++ b/setup.py
@@ -345,7 +345,7 @@ def find_data_files(manpath="share/man"):
 
 setup(
 	name="fonttools",
-	version="4.5.0",
+	version="4.5.1.dev0",
 	description="Tools to manipulate font files",
 	author="Just van Rossum",
 	author_email="just@letterror.com",