diff --git a/third-party/chpl-venv/c2chapel-requirements.txt b/third-party/chpl-venv/c2chapel-requirements.txt
index 8930fa110534..525c5e8fb101 100644
--- a/third-party/chpl-venv/c2chapel-requirements.txt
+++ b/third-party/chpl-venv/c2chapel-requirements.txt
@@ -1,3 +1,3 @@
 # tools/c2chapel/Makefile should match so fakeHeaders download matches
-pycparser==2.22
-pycparserext
+pycparser==2.20
+pycparserext==2021.1
diff --git a/tools/c2chapel/Makefile b/tools/c2chapel/Makefile
index a72cab4fbac9..52baecbd84e4 100644
--- a/tools/c2chapel/Makefile
+++ b/tools/c2chapel/Makefile
@@ -35,7 +35,7 @@ link=$(bdir)/c2chapel
 
 # Note, this version is used only for the fake headers,
 # but it should probably match third-party/chpl-venv/c2chapel-requirements.txt
-VERSION=2.22
+VERSION=2.20
 TAR=release_v$(VERSION).tar.gz
 
 RELEASE=https://github.com/eliben/pycparser/archive/$(TAR)