diff --git a/setup.py b/setup.py
index fba4d55..4df6999 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@
 install_requires = [
     'argparse',
     'biopython>=1.70,<=1.76', # support for structured comments from version 1.70, removed Alphabet in version 1.78
-    'scikit-learn>=0.18.2', # needed for antiSMASH compatibility
+    'scikit-learn>=0.18.2,<=0.21.3', # sklearn with random forest compatibility
     'pandas>=0.24.1',
     'numpy>=1.16.1,<1.17',
     'keras>=2.2.4,<2.3.0',