diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6146d03..234f9b5 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
       max-parallel: 3
       matrix:
         platform: [ubuntu-latest]
-        python-version: ["3.7", "3.8", "3.9"]
+        python-version: ["3.7", "3.8", "3.9"] # 3.10, 3.11 is not yet supported
 
     steps:
     - uses: actions/checkout@v2
diff --git a/pqkmeans/encoder/pq_encoder.py b/pqkmeans/encoder/pq_encoder.py
index 513b9fb..9ac922a 100644
--- a/pqkmeans/encoder/pq_encoder.py
+++ b/pqkmeans/encoder/pq_encoder.py
@@ -22,9 +22,9 @@ def fit(self, x_train):
         self.Ds = int(D / self.M)
         assert self.trained_encoder is None, "fit must be called only once"
 
-        codewords = numpy.zeros((self.M, self.Ks, self.Ds), dtype=numpy.float)
+        codewords = numpy.zeros((self.M, self.Ks, self.Ds), dtype=float)
         for m in range(self.M):
-            x_train_sub = x_train[:, m * self.Ds: (m + 1) * self.Ds].astype(numpy.float)
+            x_train_sub = x_train[:, m * self.Ds: (m + 1) * self.Ds].astype(float)
             codewords[m], _ = kmeans2(x_train_sub, self.Ks, iter=self.iteration, minit='points')
         self.trained_encoder = TrainedPQEncoder(codewords, self.code_dtype)
 
@@ -66,7 +66,7 @@ def decode_multi(self, codes):
         assert M == self.M
         assert codes.dtype == self.code_dtype
         
-        decoded = numpy.empty((N, self.Ds * self.M), dtype=numpy.float)
+        decoded = numpy.empty((N, self.Ds * self.M), dtype=float)
         for m in range(self.M):
             decoded[:, m * self.Ds: (m + 1) * self.Ds] = self.codewords[m][codes[:, m], :]
         return decoded