The exclusive use of the E.FIRMA (Advanced Electronic Signature) has been established as the only valid digital certificate for processing employer affiliation transactions and linking legal representatives, exclusively through the IMSS Virtual Desk (Escritorio Virtual).

According to the Official Gazette of the Federation (DOF) published on July 16, 2026, the following key provisions were announced:

• Exclusive use of the Advanced Electronic Signature (E.FIRMA) issued by the Mexican Tax Administration Service (SAT).
• Legal representatives and authorized individuals must be linked exclusively through the IMSS Virtual Desk, where authentication must be completed using their personal E.FIRMA.
• The Employer Electronic Identification Number (NPIE) and the IMSS Digital Certificate are repealed. Accordingly, Agreements 43/2004 and 533/2006 are revoked. These agreements previously governed the issuance, use, legal effects, security, cancellation, and revocation of the NPIE and the IMSS Digital Certificate, as well as the linkage of branch office NPIEs to the parent company's NPIE to centralize electronic processing of filings, inquiries, authorizations, and the issuance of additional digital certificates for designated personnel.
• A 90-calendar-day transition period is granted, effective from the publication date of the Agreement in the Official Gazette, allowing employers and other obligated parties to migrate to the exclusive use of the E.FIRMA. 

This Agreement entered into force on July 17, 2026, following its publication in the Official Gazette of the Federation (DOF on July 16, 2026).

J.A. DEL RÍO offers a wide array of specialized consulting services to assist you with these and other matters, in order to ensure that your project complies with the applicable characteristics  contained in this agreement.

If you have any questions, J.A. DEL RÍO can provide you with our experts to advise in matters concerning compliance with your legal and tax obligations. Once again, please let us know if we may be of any further assistance to you at: contacto@jadelrio.com.o you at: contacto@jadelrio.com.