diff --git a/artiq-fast/conda-windows/llvmlite-artiq.nix b/artiq-fast/conda-windows/llvmlite-artiq.nix
index 3bfd98a..51eaafc 100644
--- a/artiq-fast/conda-windows/llvmlite-artiq.nix
+++ b/artiq-fast/conda-windows/llvmlite-artiq.nix
@@ -36,6 +36,8 @@ let
         build:
           - cmake
           - llvm-or1k
+        run:
+          - python<3.8
       EOF
 
       cat > bld.bat << EOF
diff --git a/artiq-fast/conda/llvmlite-artiq.nix b/artiq-fast/conda/llvmlite-artiq.nix
index 3e90076..a6aa4ed 100644
--- a/artiq-fast/conda/llvmlite-artiq.nix
+++ b/artiq-fast/conda/llvmlite-artiq.nix
@@ -25,7 +25,7 @@ let
     # that they are not there if they have been installed from files.
     requirements:
       run:
-        - python
+        - python<3.8
         - ncurses [linux]
     EOF