diff --git a/docs/README.md b/docs/README.md
index f1bc71671..b1bac65e9 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -2,10 +2,12 @@
 Sphinx Documentation
 ====================
 
+In project root
 ```
-pip install -r requirements.txt
+pip install -r requirements-dev.txt
 ```
 
+In this directory
 ```
 make -C docs html
 ```
diff --git a/docs/requirements.txt b/docs/requirements.txt
deleted file mode 100644
index 6966869c7..000000000
--- a/docs/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-sphinx
diff --git a/requirements-dev.txt b/requirements-dev.txt
index f6a723200..6f87f2fbc 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -27,3 +27,6 @@ pytest-mock>=3.6.1
 teamcity-messages>=1.29
 tox>=3.27.1
 tox-factor>=0.1.2
+
+# needed for building docs
+sphinx
diff --git a/testkit/build.py b/testkit/build.py
index cf926cb74..50b2fff8a 100644
--- a/testkit/build.py
+++ b/testkit/build.py
@@ -29,4 +29,5 @@
 
 if __name__ == "__main__":
     run_python(["-m", "pip", "install", "-U", "pip"])
-    run_python(["-m", "pip", "install", "-Ur", "requirements-dev.txt"])
+    run_python(["-m", "pip", "install", "--use-pep517", "-Ur",
+                "requirements-dev.txt"])