diff --git a/.circleci/config.yml b/.circleci/config.yml
index e503679ed..f3965d242 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -89,7 +89,7 @@ workflows:
 
       - "nixos":
           name: "<<matrix.pythonVersion>>"
-          nixpkgs: "22.11"
+          nixpkgs: "22_11"
           matrix:
             parameters:
               pythonVersion: