diff --git a/core/base/inc/TEnv.h b/core/base/inc/TEnv.h
index 99d2614a3c938bbde6f4a7718177c70cfbd55dc9..62cc47d5b6e99e7c295ac6c7d51e9f5d5a4d6626 100644
--- a/core/base/inc/TEnv.h
+++ b/core/base/inc/TEnv.h
@@ -163,7 +163,7 @@ public:
    virtual void        PrintEnv(EEnvLevel level = kEnvAll) const;
    Bool_t              IgnoreDuplicates(Bool_t ignore);
 
-   ClassDef(TEnv,1)  // Handle ROOT configuration resources
+   ClassDef(TEnv,2)  // Handle ROOT configuration resources
 };
 
 R__EXTERN TEnv *gEnv;