diff --git a/noxfile.py b/noxfile.py
index ceee78b..34abad4 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -98,14 +98,12 @@ def tests(session):
     args = session.posargs or ["--cov=adijif"]
     install_with_constraints(
         session,
+        ".[cplex,gekko]",
         "pytest",
         "pytest-cov",
         "pytest-xdist",
         "pytest-mock",
-        "gekko",
         "numpy",
-        "cplex",
-        "docplex==2.23.222",
         "coverage[toml]",
     )
     session.run("pytest", *args)
@@ -118,14 +116,12 @@ def testsp(session):
     args = [f"-n={os.cpu_count()}"] or ["--cov=adijif"]
     install_with_constraints(
         session,
+        ".[cplex,gekko]",
         "pytest",
         "pytest-cov",
         "pytest-xdist",
         "pytest-mock",
-        "gekko",
         "numpy",
-        "cplex",
-        "docplex",
         "coverage[toml]",
     )
     session.run("pytest", *args)
diff --git a/pyproject.toml b/pyproject.toml
index a3eae51..5266b37 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -13,7 +13,7 @@ requires-python = ">=3.7"
 dependencies = ["numpy"]
 
 [project.optional-dependencies]
-cplex = ["cplex", "docplex"]
+cplex = ["cplex", "docplex==2.24.231"]
 gekko = ["gekko"]
 
 [tool.coverage.paths]