In 2012, Mexico City’s Fourth Civil Court of Appeals issued the following Decision entitled “DOCUMENTS AND ELECTRONIC MAIL. THEIR EVIDENTIARY WEIGHT IN COMMERCIAL LAW.” This holding set forth the level of security and reliability given under Mexican law to electronic signatures and emails offered as evidence at trial, therefore establishing the probative value of each. Such holding provides that an advance electronic signature shall prevail over a simple electronic or digital signature because the requirements of an advance electronic signature make it more reliable than the latter. An e-mail containing an advance electronic signature which is offered as evidence at trial will have the same probative value as a physically signed document. On the contrary, if the document was not issued with an advance electronic signature, an expert witness must authenticate the document. Lastly, if a printed version of an email is offered as evidence, it will have the same probative value as a regular document. For these reasons, the most reliable manner in which to sign an electronic or digital document is to sign by means of an advance electronic signature. In regard to emails, it is necessary to maintain such and offer the digital version as evidence until such time as there is an e-mail service provider that requires a verifiable electronic signature.