The article considers the problem of personal biometric data “aging” over time. A method has been proposed to overcome this problem by automatically updating the specified data in the biometric system storage using the speech signals of registered users obtained during latest requests for their identification and online service. The proposed method uses a scale-invariant indicator of the voice template quality. As a result, it is characterized by guaranteed reliability of the decisions made in the conditions of a wide speech signal dynamic range. It was established that the use of a scale-invariant indicator provides the guaranteed significance level of decisions made by a conventional observer. A full-scale experiment implementing the proposed method has been set up and carried out using an authoring software; practical justification for the effectiveness of the proposed method with real speech data has been given. The results obtained are intended for using in the development of new and modernization of existing systems and technologies for automated quality control and updating of personal biometric data.