diff --git a/CHANGES.md b/CHANGES.md
index 2dec497..ac0cd6f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,4 @@
-## Version 0.9.0 (in development)
+## Version 0.9.0
 
 * Added support for nested Zarr structures represented by `xarray.DataTree`,
   including atomic rollback of complete DataTree slices and optional per-group
diff --git a/zappend/__init__.py b/zappend/__init__.py
index 6b96f67..51d5a20 100644
--- a/zappend/__init__.py
+++ b/zappend/__init__.py
@@ -2,4 +2,4 @@
 #  Permissions are hereby granted under the terms of the MIT License:
 #  https://opensource.org/licenses/MIT.
 
-__version__ = "0.9.0.dev0"
+__version__ = "0.9.0"