diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..e8698a93
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,5 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+
+[tool.black]
+line-length = 121
diff --git a/script/release b/script/release
index 0f98e3ef..24032756 100755
--- a/script/release
+++ b/script/release
@@ -45,9 +45,9 @@ auto_prepare_release() {
 		last_tag=$(git tag --sort=-version:refname |head -n1)
 		last_tag=${last_tag##v}
 		version_replace="${last_tag}.post$(date -u +%y%m%d%H%M)"
-		update_version "setup.py" "s/VERSION =.+/VERSION = '$version_replace'/"
-		update_version "python2/httplib2/__init__.py" "s/__version__ =.+/__version__ = '$version_replace'/"
-		update_version "python3/httplib2/__init__.py" "s/__version__ =.+/__version__ = '$version_replace'/"
+		update_version "setup.py" "s/VERSION =.+/VERSION = \"$version_replace\"/"
+		update_version "python2/httplib2/__init__.py" "s/__version__ =.+/__version__ = \"$version_replace\"/"
+		update_version "python3/httplib2/__init__.py" "s/__version__ =.+/__version__ = \"$version_replace\"/"
 		version_check "$version_replace"
 	fi
 }
@@ -132,9 +132,9 @@ bump_version() {
 	fi
 	echo "Next version:    '$version_next'" >&2
 
-	update_version "python3/httplib2/__init__.py" "s/__version__ =.+/__version__ = '$version_next'/"
-	update_version "python2/httplib2/__init__.py" "s/__version__ =.+/__version__ = '$version_next'/"
-	update_version "setup.py" "s/VERSION =.+/VERSION = '$version_next'/"
+	update_version "python3/httplib2/__init__.py" "s/__version__ =.+/__version__ = \"$version_next\"/"
+	update_version "python2/httplib2/__init__.py" "s/__version__ =.+/__version__ = \"$version_next\"/"
+	update_version "setup.py" "s/VERSION =.+/VERSION = \"$version_next\"/"
 
 	confirm "Confirm changes? [yN] " || exit 1
 }
@@ -142,8 +142,8 @@ bump_version() {
 update_version() {
 	local path="$1"
 	local sed_expr="$2"
-		# sed -E --in-place='' -e "s/VERSION =.+/VERSION = '$version_replace'/" setup.py
-		# sed -E --in-place='' -e "s/__version__ =.+/__version__ = '$version_replace'/" python2/httplib2/__init__.py python3/httplib2/__init__.py
+		# sed -E --in-place='' -e "s/VERSION =.+/VERSION = \"$version_replace\"/" setup.py
+		# sed -E --in-place='' -e "s/__version__ =.+/__version__ = \"$version_replace\"/" python2/httplib2/__init__.py python3/httplib2/__init__.py
 	echo "Updating file '$path'" >&2
 	if ! sed -E --in-place='' -e "$sed_expr" "$path" ; then
 		echo "sed error $?" >&2
@@ -209,7 +209,7 @@ assert_tree_clean() {
 
 version_check() {
 	local need=$1
-	local version_setup=$(fgrep 'VERSION =' setup.py |tr -d " '" |cut -d\= -f2)
+	local version_setup=$(fgrep 'VERSION =' setup.py |tr -d " '\"" |cut -d\= -f2)
 	local version_py2=$(cd python2 ; python2 -Es -c 'import httplib2;print(httplib2.__version__)')
 	local version_py3=$(cd python3 ; python3 -Es -c 'import httplib2;print(httplib2.__version__)')
 	if [[ "$version_setup" != "$need" ]] ; then