diff --git a/Makefile b/Makefile
index 0242819..d856041 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@
 
 # Create the virtualenv with all the tools installed
 doc_venv:
-	virtualenv doc_venv ;\
+	virtualenv -p python3 doc_venv ;\
 	source $@/bin/activate ;\
 	pip install livereload ;\
 	pip install -r requirements.txt
@@ -80,7 +80,7 @@
 	  then git clone $(REPO_HOST)/$(@F) $@ ;\
 	fi
 
-# checkout correct ref if not under test, then link subdirectories into main
+# checkout correct ref if not under test, then copy subdirectories into main
 # docs dir
 $(OTHER_REPO_DOCS): | $(CHECKOUT_REPOS)
 	if [ "$(SKIP_CHECKOUT)" != "$@" ] ;\
@@ -88,7 +88,7 @@
 	  cd "repos/$@" && git checkout $$GIT_REF ;\
 	fi
 	GIT_SUBDIR=`grep '^$@ ' git_refs | awk '{print $$2}'` ;\
-	ln -s repos/$(@)$$GIT_SUBDIR $@ ;\
+	cp -r repos/$(@)$$GIT_SUBDIR $@ ;\
 
 # Build Robot documentation in voltha-system-tests and copy it into _static.
 _static/voltha-system-tests: | $(OTHER_REPO_DOCS)
diff --git a/requirements.txt b/requirements.txt
index d523bef..6f4c716 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,22 +1,22 @@
-Sphinx~=1.8.5
-actdiag~=0.5.4
+Sphinx~=2.4.3
+actdiag~=2.0.0
 blockdiag~=1.5.4
 doc8~=0.8.0
 livereload~=2.6.1
-nwdiag~=1.0.4
+nwdiag~=2.0.0
 recommonmark~=0.6.0
-seqdiag~=0.9.6
+seqdiag~=2.0.0
 sphinx-reload~=0.2.0
 sphinx-rtd-theme~=0.4.3
-sphinxcontrib-actdiag~=0.8.5
-sphinxcontrib-blockdiag~=1.5.5
-sphinxcontrib-nwdiag~=0.9.5
-sphinxcontrib-openapi~=0.5.0
-sphinxcontrib-seqdiag~=0.8.5
-sphinxcontrib-spelling~=4.2.1
+sphinxcontrib-actdiag~=2.0.0
+sphinxcontrib-blockdiag~=2.0.0
+sphinxcontrib-nwdiag~=2.0.0
+sphinxcontrib-openapi~=0.6.0
+sphinxcontrib-seqdiag~=2.0.0
+sphinxcontrib-spelling~=4.3.0
 # using a fork as the main branch is broken in newer sphinx, per:
 # https://github.com/sphinx-contrib/sphinxcontrib-versioning/issues/58
 # also added functionality to support working with other repos
 git+https://github.com/zdw/sphinxcontrib-versioning@0998d870b2791eb6343c98e98d6680c1e727daee
 # sphinx-autoapi~=1.2.1
-# sphinxcontrib-golangdomain
+# sphinxcontrib-golangdomain==0.2.0.dev0