diff --git a/nix/build-all.py b/nix/build-all.py
index 1fcca500c2..4148131527 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -88,7 +88,7 @@ BOOST_VERSION="1.59.0"
 #PCRE_VERSION="8.39"
 PCRE_VERSION="8.43"
 #LIBXML2_VERSION="2.9.3"
-LIBXML2_VERSION="2.9.9_2"
+LIBXML2_VERSION="2.9.9"
 #CMAKE_VERSION="3.4.1"
 CMAKE_VERSION="3.14.5"
 SWIG_VERSION="3.0.12"