diff --git a/gymnasium/envs/mujoco/assets/swimmer.xml b/gymnasium/envs/mujoco/assets/swimmer.xml
index a12287722..456d95f5e 100644
--- a/gymnasium/envs/mujoco/assets/swimmer.xml
+++ b/gymnasium/envs/mujoco/assets/swimmer.xml
@@ -1,8 +1,8 @@
 <mujoco model="swimmer">
   <compiler angle="degree" coordinate="local" inertiafromgeom="true"/>
-  <option collision="predefined" density="4000" integrator="RK4" timestep="0.01" viscosity="0.1"/>
+  <option density="4000" integrator="RK4" timestep="0.01" viscosity="0.1"/>
   <default>
-    <geom conaffinity="1" condim="1" contype="1" material="geom" rgba="0.8 0.6 .4 1"/>
+    <geom conaffinity="0" condim="1" contype="0" material="geom" rgba="0.8 0.6 .4 1"/>
     <joint armature='0.1'  />
   </default>
   <asset>
@@ -14,7 +14,7 @@
   </asset>
   <worldbody>
     <light cutoff="100" diffuse="1 1 1" dir="-0 0 -1.3" directional="true" exponent="1" pos="0 0 1.3" specular=".1 .1 .1"/>
-    <geom conaffinity="1" condim="3" material="MatPlane" name="floor" pos="0 0 -0.1" rgba="0.8 0.9 0.8 1" size="40 40 0.1" type="plane"/>
+    <geom condim="3" material="MatPlane" name="floor" pos="0 0 -0.1" rgba="0.8 0.9 0.8 1" size="40 40 0.1" type="plane"/>
     <!--  ================= SWIMMER ================= /-->
     <body name="torso" pos="0 0 0">
       <camera name="track" mode="trackcom" pos="0 -3 3" xyaxes="1 0 0 0 1 1"/>
diff --git a/gymnasium/envs/mujoco/mujoco_rendering.py b/gymnasium/envs/mujoco/mujoco_rendering.py
index a5681a68d..e5e45b875 100644
--- a/gymnasium/envs/mujoco/mujoco_rendering.py
+++ b/gymnasium/envs/mujoco/mujoco_rendering.py
@@ -611,7 +611,7 @@ def _create_overlay(self):
 
         self.add_overlay(bottomleft, "FPS", "%d%s" % (1 / self._time_per_render, ""))
         self.add_overlay(
-            bottomleft, "Solver iterations", str(self.data.solver_iter + 1)
+            bottomleft, "Solver iterations", str(self.data.solver_niter[0] + 1)
         )
         self.add_overlay(
             bottomleft, "Step", str(round(self.data.time / self.model.opt.timestep))
diff --git a/pyproject.toml b/pyproject.toml
index 37a7d112a..b4fb30632 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,7 +41,7 @@ classic-control = ["pygame >=2.1.3"]
 classic_control = ["pygame >=2.1.3"]  # kept for backward compatibility
 mujoco-py = ["mujoco-py >=2.1,<2.2", "cython<3"]
 mujoco_py = ["mujoco-py >=2.1,<2.2", "cython<3"]       # kept for backward compatibility
-mujoco = ["mujoco >=2.3.3", "imageio >=2.14.1"]
+mujoco = ["mujoco >=3.0.0", "imageio >=2.14.1"]
 toy-text = ["pygame >=2.1.3"]
 toy_text = ["pygame >=2.1.3"]         # kept for backward compatibility
 jax = ["jax >=0.4.0", "jaxlib >=0.4.0"]
@@ -67,7 +67,7 @@ all = [
     "mujoco-py >=2.1,<2.2",
     "cython<3",
     # mujoco
-    "mujoco >=2.3.3",
+    "mujoco >=3.0.0",
     "imageio >=2.14.1",
     # toy-text
     "pygame >=2.1.3",
