diff --git a/pyproject.toml b/pyproject.toml
index ba22227..fbceb2e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pykoopman"
-version = "1.1.0"
+version = "1.1.1"
 authors = [
     { name = "Shaowu Pan", email = "shawnpan@uw.edu" },
     { name = "Eurika Kaiser", email = "eurika@uw.edu" },
@@ -26,7 +26,7 @@ classifiers = [
     "Topic :: Scientific/Engineering :: Mathematics",
 ]
 dependencies = [
-    "matplotlib <= 3.5.0, >=3.5.0",
+    "matplotlib >=3.6.0",
     "derivative ~= 0.6.0",
     "scikit-learn >= 1.1.3, <= 1.1.3",
     "numpy >=1.20, <= 1.26",
diff --git a/requirements.txt b/requirements.txt
index 7de4f70..ad57159 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-matplotlib == 3.5.0
+matplotlib >= 3.6.0
 derivative ~= 0.6.0
 scikit-learn == 1.1.3
 numpy >= 1.20, <= 1.26
diff --git a/src/pykoopman/koopman.py b/src/pykoopman/koopman.py
index 192c2d3..3aefe07 100644
--- a/src/pykoopman/koopman.py
+++ b/src/pykoopman/koopman.py
@@ -289,7 +289,7 @@ def simulate(self, x0, u=None, n_steps=1):
                 # tmp = self.W @ self.lamda**(k+1) @ y[0].reshape(-1,1)
                 y[k + 1] = self.lamda @ y[k]
             x = np.transpose(self.W @ y.T)
-            x = x.astype(self.A.dtype)
+            # x = x.astype(self.A.dtype)
         else:
             # lifted space (not eigen)
             y[0] = self.A @ self.phi(x0).flatten() + self.B @ u[0]
@@ -299,8 +299,10 @@ def simulate(self, x0, u=None, n_steps=1):
                 tmp = self.A @ y[k].reshape(-1, 1) + self.B @ u[k + 1].reshape(-1, 1)
                 y[k + 1] = tmp.flatten()
             x = np.transpose(self.C @ y.T)
-            x = x.astype(self.A.dtype)
+            # x = x.astype(self.A.dtype)
 
+        if np.isrealobj(x0):
+            x = np.real(x)
         return x
 
     def get_feature_names(self, input_features=None):