diff --git a/ippisite/db.sqlite3 b/ippisite/db.sqlite3
index c001ec8925ad7552ff693656cfa7ed36d53a26ac..6430ce79dc3918445cd0c1827ab28e62ccb5c839 100644
Binary files a/ippisite/db.sqlite3 and b/ippisite/db.sqlite3 differ
diff --git a/ippisite/requirements-core.txt b/ippisite/requirements-core.txt
index e340d8979a2cf5ff3b7d47b29f30b1e0b2a232bb..5772327b47eaed2750e112f7ec4732e33dc288eb 100644
--- a/ippisite/requirements-core.txt
+++ b/ippisite/requirements-core.txt
@@ -13,7 +13,7 @@ bioservices
 bioblend
 bs4
 # libraries to compute PCA
-sklearn
+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
 matplotlib==2.2.3 #Matplotlib 3.0+ does not support Python 2.x, 3.0, 3.1, 3.2, 3.3, or 3.4.
 # postgres driver