Hi: For example, we added a new field in a node in primnodes.h
struct FuncExpr { + int newf; }; then we modified the copy/read/out functions for this node. In _readFuncExpr, we probably add something like static FuncExpr _readFuncExpr(..) { .. + READ_INT_FILED(newf); }; Then we will get a compatible issue if we create a view with the node in the older version and access the view with the new binary. I think we can have bypass this issue easily with something like READ_INT_FIELD_UNMUST(newf, defaultvalue); However I didn't see any code like this in our code base. does it doesn't work or is it something not worth doing? -- Best Regards Andy Fan