I need to reorder a previously existing product, such as M-xxxxxx-00. Has it been redesigned?

Check the website to find the current catalog number - the first 2-digit number will indicate the version. If its different than what you ordered, then it has been versioned. You may contact Technical Support (Ts.dharmacon@horizondiscovery.com) for details on how this product has changed. Any sequences no longer available in the pre-designed catalog are available through custom synthesis.