diff --git a/spack.yaml b/spack.yaml
index 2d370cef42c6c6762b9c5147f479e473ba0402ce..37296648235200b4adb490c6642023f5ecebc3ef 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -24,4 +24,4 @@ spack:
     - py-formencode %gcc@10.3.0
     - tvb-framework ^binutils+ld+gold %gcc@10.3.0
     - meta-brainscales %gcc@10.3.0
-    - pynn-brainscales %gcc@10.3.0
+    - pynn-brainscales@1.0-rc2 %gcc@10.3.0