diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90c63b0..c3e4e2d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# 0.17.0
+
+- Significant change in Python organization: there are now model-specific System class, rather than one System class.  Tileset definitions will return a specific class, and classes should eventually be able to be created directly.  This should make it much easier to add ways to view and manipulate system objects in model-dependent ways.
+- Improvements to Python docstrings and type stubs.
+- Numerous code rearrangements for Python.
+
 # 0.16.0
 
 - Improvements to FFS code organization.
diff --git a/py-rgrow/pyproject.toml b/py-rgrow/pyproject.toml
index 1cefb70..db07965 100644
--- a/py-rgrow/pyproject.toml
+++ b/py-rgrow/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "rgrow"
-dependencies = ["numpy ~= 1.26", "attrs ~= 23.2", "matplotlib ~= 3.8.2"]
+dependencies = ["numpy ~= 1.26", "attrs ~= 23.2", "matplotlib ~= 3.8.2", "typing_extensions"]
 requires-python = ">=3.9"
 
 [project.optional-dependencies]
diff --git a/py-rgrow/rgrow/rgrow.pyi b/py-rgrow/rgrow/rgrow.pyi
index 2e19dc8..13dad4a 100644
--- a/py-rgrow/rgrow/rgrow.pyi
+++ b/py-rgrow/rgrow/rgrow.pyi
@@ -1,6 +1,7 @@
 # flake8: noqa: PYI021
-from typing import Any, List, Sequence, Self, TypeAlias, overload
-from numpy import dtype, ndarray
+from typing import Any, List, Sequence
+from typing_extensions import Self, TypeAlias, overload
+from numpy import ndarray
 import numpy as np
 import polars as pl
 from numpy.typing import NDArray