diff --git a/build/pkgs/gmpy2/install-requires.txt b/build/pkgs/gmpy2/install-requires.txt
index 5f50ec2dd25..11116398187 100644
--- a/build/pkgs/gmpy2/install-requires.txt
+++ b/build/pkgs/gmpy2/install-requires.txt
@@ -1 +1 @@
-gmpy2 >=2.1.0
+gmpy2 ~=2.1.b999