diff --git a/CHANGELOG.md b/CHANGELOG.md
index 766a920..1008756 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,9 +1,19 @@
 # Changelog
 
-_Current version: 0.0.22_
+_Current version: 0.0.23_
 
 [PyPi link](https://pypi.org/project/l2m2/)
 
+### 0.0.23 - June 30, 2024
+
+#### Fixed
+
+- Major bug where l2m2 would cause environments without `typing_extensions` installed to crash due to it not being listed as an external dependency. This has been fixed by removing the dependency on `typing_extensions` in the code and replacing it with Python3.9-compatible type hints.
+
+#### Changed
+
+- blah blah blah
+
 ### 0.0.22 - June 22, 2024
 
 #### Fixed
diff --git a/Makefile b/Makefile
index 74afdd2..d16bf84 100644
--- a/Makefile
+++ b/Makefile
@@ -13,10 +13,17 @@ init:
 test:
 	pytest -v --cov=l2m2 --cov-report=term-missing --failed-first --durations=0
 
-itest:
+clear-deps:
+	@pip uninstall -y l2m2 > /dev/null 2>&1
+	@pip freeze | xargs pip uninstall -y > /dev/null
+
+itest-run:
 	@pip install dist/l2m2-$(VERSION)-py3-none-any.whl > /dev/null
+	@pip install python-dotenv > /dev/null
 	python integration_tests/itests.py
-	@pip uninstall -y l2m2 > /dev/null
+
+itest: clear-deps itest-run clear-deps
+
 
 coverage:
 	pytest --cov=l2m2 --cov-report=html
diff --git a/README.md b/README.md
index 3346139..5d9bb21 100644
--- a/README.md
+++ b/README.md
@@ -579,8 +579,9 @@ Contributions are welcome! Contributing requires Python >= 3.9 and [GNU Make](ht
   - Create a `.env` file with your API keys, and copy `itests.example.py` to `itests.py`.
   - Write your integration tests in `itests.py`.
   - Run locally with `python itests.py -l`.
-    - Make sure to pass the `-l` flag or else it will look for an L2M2 distribution. Additionally, make sure l2m2 is not installed with pip when running the integration tests locally.
+    - _Note: make sure to pass the `-l` flag or else it will look for an L2M2 distribution. Additionally, make sure l2m2 is not installed with pip when running the integration tests locally._
   - Once your changes are ready, from the top-level directory run `make build` to create the distribution and `make itest` to run your integration tests against the distribution.
+    - _Note: in order to ensure a clean test environment, `make itest` uninstalls all third-party Python packages before running the tests, so make sure to run `make init` when you're done working on integration tests._
 - **Contribute**
   - Create a PR and ping me for a review.
   - Merge!
diff --git a/l2m2/model_info.py b/l2m2/model_info.py
index b57e69e..45bc32b 100644
--- a/l2m2/model_info.py
+++ b/l2m2/model_info.py
@@ -1,7 +1,7 @@
 """Information about models and providers supported by L2M2."""
 
-from typing import Dict, Union, Any
-from typing_extensions import TypedDict, NotRequired, TypeVar, Generic, Literal
+from typing import Dict, Union, Any, TypedDict, Literal, TypeVar, Generic
+
 from enum import Enum
 import sys
 
@@ -22,15 +22,19 @@ class ProviderEntry(TypedDict):
 MODEL_ID = "<<MODEL_ID>>"
 
 
-class Param(TypedDict, Generic[T]):
-    custom_key: NotRequired[str]
+class ParamBase(TypedDict, Generic[T]):
     default: Union[T, Literal[Marker.PROVIDER_DEFAULT]]
     max: T
 
 
+class ParamExt(ParamBase[T], total=False):
+    custom_key: str
+    abc: str
+
+
 class ModelParams(TypedDict):
-    temperature: Param[float]
-    max_tokens: Param[int]
+    temperature: Union[ParamBase[float], ParamExt[float]]
+    max_tokens: Union[ParamBase[int], ParamExt[int]]
 
 
 ParamName = Literal[