The API of Zend_Validate has changed from time to time. If you started to use Zend_Validate and its subcomponents in earlier versions follow the guidelines below to migrate your scripts to use the new API. When setting returning a error from within a self written validator you have to call the _error() method. Before Zend Framework 1.10 you were able to call this method without giving a parameter. It used then the first found message template. This behaviour is problematic when you have validators with more than one different message to be returned. Also when you extend an existing validator you can get unexpected results. This could lead to the problem that your user get not the message you expected. _error(); // unexpected results between different OS ... } } ]]> To prevent this problem the _error() method is no longer allowed to be called without giving a parameter. _error(self::MY_ERROR); // defined error, no unexpected results ... } } ]]> Before Zend Framework 1.10 2 identical messages were thrown within the date validator. These were NOT_YYYY_MM_DD and FALSEFORMAT. As of Zend Framework 1.10 only the FALSEFORMAT message will be returned when the given date does not match the set format. Before Zend Framework 1.10 the messages within the 2 barcode adapters, the Alpha and the Alnum validator were identical. This introduced problems when using custom messages, translations or multiple instances of these validators. As with Zend Framework 1.10 the values of the constants were changed to be unique. When you used the constants as proposed in the manual there is no change for you. But when you used the content of the constants in your code then you will have to change them. The following table shows you the changed values: Validator Constant Value Alnum STRING_EMPTY alnumStringEmpty Alpha STRING_EMPTY alphaStringEmpty Barcode_Ean13 INVALID ean13Invalid Barcode_Ean13 INVALID_LENGTH ean13InvalidLength Barcode_UpcA INVALID upcaInvalid Barcode_UpcA INVALID_LENGTH upcaInvalidLength Digits STRING_EMPTY digitsStringEmpty