diff --git a/pyproject.toml b/pyproject.toml
index d6a215b1c..1782de9dd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,6 +19,7 @@ classifiers = [
   "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
   "Topic :: Communications",
   "Topic :: Utilities",
 ]
@@ -43,6 +44,7 @@ test = [
   "hypothesis",
   "packaging",
   "vdirsyncer",
+  { version = "pkg_resources", python = ">=3.12" }
 ]
 docs = [
   "sphinx!=1.6.1",