diff --git a/requirements.txt b/requirements.txt
index 24ce15ab7ead32f98c7ac3edcd34bb2010ff4326..56aacd774b88e370f0e2fad347abb341df445332 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-numpy
+numpy >= 1.20.0 # BSD
diff --git a/tests/requirements.txt b/tests/requirements.txt
index c28d83eb59417e45937be95328d3224a587a81d7..ada64140f70e847fe9bc4e95f51aebc9e326a9e5 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -1,6 +1,6 @@
-black
-build
-flake8
-pylint
-pytest
-pytest-cov
+black >= 22.0.0 # MIT
+build >= 0.8.0 # MIT
+flake8 >= 5.0.0 # MIT
+pylint >= 2.15.0 # GPLv2
+pytest >= 7.0.0 # MIT
+pytest-cov >= 3.0.0 # MIT