diff --git a/README.md b/README.md
index c53e60e1681ea70b4b739cb99752b7e6c2fc7f95..8aca68e846041fee8c947a5410c32f7a3a60f5e4 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,10 @@ Then copy your resulting wheel and install it via pip on the target system.
 
 # Changelog
 
+## v0.5.1
+
+* _TBA_
+
 ## v0.5
 
 * if mmap is used, the kernel will be informed after loading the chunk that we 
diff --git a/setup.py b/setup.py
index b7fe35eaa552f112618a486fa2b069f5552aa62d..414591f089b23acf593e3882a55c016a8cccba0b 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@ if 'CI' in os.environ:
 
 
 setup(name='tempsdb',
-      version='0.5',
+      version='0.5.1a1',
       packages=['tempsdb'],
       install_requires=['satella>=2.14.24', 'ujson', 'indexed_gzip'],
       ext_modules=build([Multibuild('tempsdb', find_pyx('tempsdb'), **ext_kwargs), ],