diff --git a/core/nwb.file.yaml b/core/nwb.file.yaml
index 7aa93515..cf97f0a7 100644
--- a/core/nwb.file.yaml
+++ b/core/nwb.file.yaml
@@ -7,7 +7,7 @@ groups:
   attributes:
   - name: nwb_version
     dtype: text
-    value: "2.5.0"
+    value: "2.6.0-alpha"
     doc: File version string. Use semantic versioning, e.g. 1.2.1. This will be the
       name of the format with trailing major, minor and patch numbers.
   datasets: