Dear clients and friends,
In order to inform you about significant changes in the filing procedures before the IMSS, particularly the implementation of the Advanced Electronic Signature (e.firma) as the only valid means of authentication, we present this informative bulletin that summarizes the most relevant aspects of the new Agreement that enters into force on July 17, 2026.
Below, we present the most relevant aspects:
What is the only valid means of authentication before the IMSS?
As of the Agreement's entry into force, the Advanced Electronic Signature (e.firma) will be the only valid means. Documents signed with e.firma will have the same evidentiary value as those signed with handwritten signature.
How are legal representatives linked to the IMSS?
Linking must be conducted exclusively through the IMSS Virtual Office. Both the representative and the represented party must authenticate and jointly sign with their respective e.firma.
What happens with the NPIE?
The use of the Electronic Employer Identification Number (NPIE) and its digital certificate are completely eliminated. This change complies with previous transitional provisions.
What is the deadline for migration?
A transition period of 90 calendar days from publication (until October 14, 2026) is granted to migrate to the exclusive use of e.firma.
Recommended actions:
• Verify e.firma validity with the SAT.
• Process e.firma renewal if necessary.
• Obtain e.firma for legal representatives and administrators.
• Link representatives through Virtual Office by October 14.
Conclusion
This digital transformation represents a significant step toward modernizing administrative processes. E.firma as a single standard strengthens document security and authenticity while streamlining procedures and reducing risks.
At Ramos, Ripoll & Schuster®, we have the necessary experience to advise you on administrative litigation, tax, and social security matters. For any inquiries related to these topics, we remain at your service.
Authors:
Octavio Vladimir González García
Julio López Gómez
Juan Ramón Lara Velázquez