diff --git a/app/boot_levels.go b/app/boot_levels.go
index 89d76ae34..3d49bf83f 100644
--- a/app/boot_levels.go
+++ b/app/boot_levels.go
@@ -32,6 +32,12 @@ import (
 	"time"
 )
 
+type (
+	storeUpgrader interface {
+		Upgrade(context.Context, *zap.Logger) error
+	}
+)
+
 const (
 	bootLevelWaiting = iota
 	bootLevelSetup