diff --git a/spack.yaml b/spack.yaml
index 0a5a450cb795edd48a22f9707d6c18ad9737c6eb..dd0c326ca4884f3d778b3d39d8ea8251d99e9f06 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -21,7 +21,7 @@ spack:
     - nest@3.3 +python +gsl +mpi
     - arbor +python +mpi ^python@3:3.9
     - neuron +mpi
-    - py-pynn@0.10.0
+    - py-pynn@0.9.6
     - tvb-data
     - tvb-library ^py-numba@0.54.0 ^binutils+ld+gold
     - tvb-storage ^binutils+ld+gold