diff --git a/tools/requirements.txt b/tools/requirements.txt
index a8b72f6c..1940023e 100644
--- a/tools/requirements.txt
+++ b/tools/requirements.txt
@@ -1,5 +1,5 @@
 crossref_commons>=0.0.7
-numpy>=1.20.1
+numpy==1.19.5
 GitPython>=3.1.14
 PyYAML>=5.4.1
-TexSoup>=0.3.1
+TexSoup==0.2.1