diff --git a/pyproject.toml b/pyproject.toml
index 97cde92..20ee5a6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ wheel.py-api = "cp312"
 
 [project]
 name = "caterpillar"
-version = "2.1.5"
+version = "2.2.0-rc"
 
 description="Library to pack and unpack structurized binary data."
 authors = [
diff --git a/src/caterpillar/__init__.py b/src/caterpillar/__init__.py
index df1f0fe..f67352c 100644
--- a/src/caterpillar/__init__.py
+++ b/src/caterpillar/__init__.py
@@ -13,7 +13,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-__version__ = "2.1.5"
+__version__ = "2.2.0-rc"
 __release__ = None
 __author__ = "MatrixEditor"