diff --git a/ippisite/requirements-core.txt b/ippisite/requirements-core.txt
index 3cde9a193238df1e27034259bba4bc5b9aed0e72..6e2676a5f70169c30563643c0fd57b5cd7171a93 100644
--- a/ippisite/requirements-core.txt
+++ b/ippisite/requirements-core.txt
@@ -17,8 +17,8 @@ bioblend
 bs4
 chembl_webresource_client
 # libraries to compute PCA
-scikit-learn==0.20.3 #later versions do not support Python<3.5
-scipy==1.2.1 #Scipy >=1.3 does not support Python<3.5
+scikit-learn==0.23.2
+scipy==1.5.2
 matplotlib==2.2.3 #Matplotlib 3.0+ does not support Python 2.x, 3.0, 3.1, 3.2, 3.3, or 3.4.
 seaborn
 # postgres driver
@@ -27,5 +27,5 @@ git+https://gitlab.pasteur.fr/hmenager/django-diu.git#egg=django_diu
 # openbabel is not installed from pip for now
 #openbabel
 django-crispy-forms
-celery
-django-polymorphic
\ No newline at end of file
+celery==4.4.7
+django-polymorphic