diff --git a/bmi_tester/_version.py b/bmi_tester/_version.py
index 6c72262..8b3e3cb 100644
--- a/bmi_tester/_version.py
+++ b/bmi_tester/_version.py
@@ -1 +1 @@
-__version__ = "0.5.7.dev0"
+__version__ = "0.5.7a0"