Qualified Timestamps and Their Expiration Date, Why It Matters for Your Long-Term Archive
Since January 1, 2024, when the Regulation on Uniform Technical and Technological Requirements and Procedures for the Storage and Protection of Archival Material and Documentary Material in Electronic Form (Official Gazette of RS 107/2021, 94/2022 and 116/2023) came into force, electronic archiving has been a full legal obligation for all legal entities in Serbia. During 2025 and 2026, the state portal E-Arhiv was activated, moving the entire process from theory into operational reality.
Most companies have by now covered the basics, appointed an archivist, drafted a List of Archival Categories, registered on the E-Arhiv portal. But there is one layer of electronic archiving that no one talks about, and that can invalidate all this effort within a few years, the qualified electronic timestamp.
What no one says out loud is that a timestamp has its own expiration date, and that this expiration is often shorter than the legal retention period of the document itself. If the timestamp is not renewed on time, the document technically remains in the system, but legally loses the very thing for which it was archived, the proof of its integrity and the exact time it was created.
In this guide, we explain what a qualified electronic timestamp is, why it expires, which regulations to follow, and what happens if it expires before the document does.
What is a Qualified Electronic Timestamp
A qualified electronic timestamp is a trust service that confirms a specific electronic document existed at a precisely defined moment in time and has not been altered since. It is linked to Coordinated Universal Time (UTC), issued by a registered qualified trust service provider, and unlike an ordinary timestamp, it carries full legal weight before courts and other institutions.
Here lies a key distinction that many people miss. An electronic signature confirms who signed the document, while a timestamp confirms when the document was created and that it has not been altered since. In an electronic archive, you need both layers, because otherwise you have proof of authorship but no reliable proof of time.
The Serbian Law on Electronic Documents, Electronic Identification and Trust Services in Electronic Business (Official Gazette of RS 94/17 and 52/21), which is largely aligned with the EU eIDAS regulation, gives qualified timestamps the same evidentiary value as a physical stamp when it comes to proving the moment a document was created.
Why Timestamps Expire
A timestamp relies technically on a cryptographic hash of the document and the digital signature of the issuer. Both of these elements weaken over time, not because someone deliberately breaks them, but because technology advances. Hash algorithms that are secure today become predictable within five or ten years. The issuer’s certificate has a validity period that cannot exceed the lifespan of the underlying infrastructure. All of this means the cryptographic guarantee of a timestamp cannot last forever, even if the law allowed it.
Regulation 107/2021, which is the primary regulation for the private sector in this area, requires creators and holders of documentary material to periodically renew the timestamp before its validity expires. The exact renewal interval is not uniformly prescribed and depends on the algorithm used and the recommendations of the qualified trust service provider. For reference, the Regulation on Office Operations of State Administration Bodies (Official Gazette of RS 21/2020, 32/2021, 14/2023) prescribes a five-year interval for state bodies, which is often taken as a reasonable benchmark for the private sector, although it is not formally binding for private entities.
To determine the correct renewal interval for your documents, it is best to consult the provider of your timestamp service and your legal advisor.
What This Looks Like in Practice
Consider the following scenario. Your company issues an electronic invoice on July 15, 2026 and applies a qualified timestamp to it. The legal retention period for the invoice is ten years, until 2036. The validity of the timestamp itself is significantly shorter, typically a few years, depending on the algorithm and the service provider.
If nothing is done between the moment of archiving and the moment the timestamp expires, the invoice is still in the system when the timestamp lapses. It can still be opened, viewed and read. But the proof of its integrity is no longer indisputable. In the event of an inspection or a commercial dispute, the other party can raise the question whether the invoice was modified after the timestamp expired, and you have no cryptographic evidence to conclusively deny it. The document is still there, but its legal weight has been weakened.
The same applies to an electronic signature accompanied by a timestamp. If it is not renewed in time, the signature gradually loses its “qualified” status and becomes merely an “electronic” signature, which is a legally much weaker category.
How Timestamp Renewal Works
Renewal is not achieved by signing the document again. Instead, a timestamp upgrade takes place, meaning a new timestamp is added on top of the existing timestamp and signature. This creates a chain of timestamps, in which each successive timestamp confirms that the previous one was valid at the moment it was renewed. As long as this chain is unbroken, the document retains full legal integrity.
Technically, this means the software managing your electronic archive must maintain a per-document ledger, know when each timestamp was issued and when it will expire, and automatically initiate renewal before the deadline. For companies with thousands of archived documents, doing this manually is not practically feasible.
Who Issues Qualified Timestamps in Serbia
According to the current state of the Register of Qualified Trust Service Providers maintained by the Serbian Ministry of Information and Telecommunications, qualified timestamp services in Serbia are provided by several entities, among them the Certification Body of the Post of Serbia, the Chamber of Commerce of Serbia (PKS CA), the Office for Information Technologies and eGovernment, Inception d.o.o. and Telekom Srbija (since March 2026).
For the public sector, state bodies and local self-government units, the Office for Information Technologies has developed the RS-GOV TSA infrastructure, which is free of charge for its users. The private sector uses one of the commercial services, with pricing based on the number of issued timestamps.
The current state of the register should be verified directly on the Ministry’s website, as the list of providers can change over time.
What Happens If Renewal Is Missed
If a timestamp expires before the document’s retention period ends, the document becomes legally contested in a technical sense. It is not deleted, it is not invalid, but it loses one layer of undeniability. In an inspection, a commercial dispute or a tax audit, the other party can claim the document may have been altered after the timestamp expired, and you cannot easily provide cryptographic proof to the contrary.
The specific legal and financial consequences depend on the type of document and the specific case, so for details it is best to consult your legal advisor. But as a general rule, a document without a valid timestamp in a long-term archive is not the same as a document with one, and this difference can be decisive at the moment you least expect it.
Why You Should Not Handle This Manually
Timestamps are issued instantly, but tracking them is a process that spans decades. A company archiving one thousand invoices, contracts and delivery notes in July 2026 will, by 2036, have several such “generations” of documents, each with its own deadlines. Manually keeping track of when each timestamp expires, when it must be renewed and who is responsible for it, is not just impractical, it is mathematically risky. One forgotten document can compromise the credibility of the entire archive at the moment of an audit.
For this reason, electronic archiving should be managed by a software solution that automatically monitors the validity of each timestamp, initiates renewal before expiration and maintains a complete audit trail of all renewals, all without human intervention.
Why Docloop
Docloop is the first licensed information intermediary of the Ministry of Finance of the Republic of Serbia for the exchange of electronic invoices and other electronic documents. Since 2018, we have built a base of more than 4,800 active clients, among them Zepter, Siemens, Würth, Swisslion, MaxBet, AbelaPharm and Prvi Partizan, as well as 200,000 indirect users.
Our electronic archive solution is part of the mojDMS platform. The system automatically applies a qualified timestamp to every document entering the archive, monitors the validity of each individual timestamp and initiates renewal before expiration, so the chain of legal validity is never broken. mojDMS integrates with over 220 ERP systems, including SAP, Pantheon and Navision, meaning you do not need to replace the software you already use.
Schedule a free consultation and in a single conversation you will get a clear picture of where your business stands in relation to the law and what the transition would look like for your specific situation.
📞 +381 11 43 50 555
📧 prodaja@docloop.rs
🌐 www.docloop.rs
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