diff --git a/lib/SPTK b/lib/SPTK
index 49a4b35..2accca9 160000
--- a/lib/SPTK
+++ b/lib/SPTK
@@ -1 +1 @@
-Subproject commit 49a4b35dcf6c4114a7ec8a8a48bb5038a756941e
+Subproject commit 2accca99be205d10fde0a4b9969cc3eba7ad930e
diff --git a/setup.py b/setup.py
index b08f46e..f2ba59b 100644
--- a/setup.py
+++ b/setup.py
@@ -163,6 +163,7 @@ def finalize_options(self):
             "types-setuptools",
             "mypy<=0.910",
             "black>=19.19b0,<=20.8",
+            "click<8.1.0",
             "flake8>=3.7,<4",
             "flake8-bugbear",
             "isort>=4.3,<5.2.0",
@@ -178,7 +179,6 @@ def finalize_options(self):
         "Programming Language :: Cython",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",