diff --git a/pyproject.toml b/pyproject.toml
index cc21819..a6cf051 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@
    description = "Minimalistic and efficient implementations of PPO and TRPL for torchrl"
    authors = [{name = "Dominik Roth", email = "mail@dominik-roth.eu"}]
    readme = "README.md"
-   requires-python = ">=3.7,<3.12"
+   requires-python = ">=3.7"
    classifiers = [
        "Development Status :: 3 - Alpha",
        "Intended Audience :: Developers",
@@ -23,9 +23,10 @@
    dependencies = [
        "numpy",
        "torch",
-       "gymnasium",
+       "gymnasium<1.0",
        "tensordict",
        "torchrl",
+       "pytest",
    ]
 
    [project.urls]
@@ -33,3 +34,4 @@
 
    [project.optional-dependencies]
    dev = ["pytest"]
+   box2d = ["swig", "gymnasium[box2d]"]