What happens when email software gets too old? 

Every piece of software has a life cycle. The final stage is called end of life (EOL). For email software specifically, end of life means the vendor will no longer release patches to fix security holes, won't update the software to work with newer systems, and will stop offering technical support when things break.

As Matt Middleton-Leal, General Manager for EMEA at Qualys, explained in ITPro's Applications and the afterlife: how businesses can manage software end of life: "End of life software is not necessarily bad. It's just not updated any more, and that can lead to vulnerabilities."

The Security Risk

According to ITPro, Datadog's 2026 State of DevSecOps report found that 87% of organizations have at least one known exploitable vulnerability in deployed services. Furthermore, services running end-of-life software versions face exploitable vulnerabilities in 50% of cases, compared with just 31% for services running supported versions.

Research cited by ITPro from end-of-life software specialists HeroDev adds that EOL systems are four times as likely to be targeted as maintained applications, and 20% of critical enterprise applications run EOL code with high-severity vulnerabilities. Middleton-Leal also noted in the same piece that "nearly half of the issues on the CISA Known Exploited Vulnerabilities list are found in outdated and unsupported software."

Research published in A Measurement Study on the (In)security of End-of-Life (EoL) Embedded Devices found that more than 1 million active EOL devices are vulnerable and that over half of the vulnerabilities discovered in those devices were found after the EOL date, meaning patches were never coming.

The Windows 10 end-of-life on 14 October 2025 brought this issue into focus. Writing in TechRadar Pro, Mike Puglia of Kaseya Labs noted that roughly 30% of small- to medium-sized business workstations had not yet upgraded to Windows 11 ahead of that deadline, leaving millions of machines exposed to unpatched vulnerabilities. TechRadar Pro also reported that between 40% and 60% of breaches worldwide involve unpatched vulnerabilities, and that in over 15% of the 3,000 penetration tests conducted by Kaseya's team, unsupported Windows operating systems were the point of compromise.

Furthermore, Lenovo's endpoint security team observed that once a platform reaches end-of-life, vulnerabilities are left wide open for cybercriminals who actively scan networks looking for exactly these weaknesses. Email software is a valuable target because it's the front door of most organizations. It carries sensitive client communications, invoices, contracts, passwords, and internal discussions. A breach through outdated email software can give attackers everything they need to cause damage.

The maintenance gap

According to Emma Woollacott, writing in ITPro, more than four in ten services rely on libraries that are no longer actively maintained, with the median dependency running 278 days behind the latest major version. In other words, even businesses that haven't formally crossed an EOL threshold may already be accumulating risk through neglected, unmaintained dependencies.

Andrew Krug, head of security advocacy at Datadog, puts it this way, "Go slow, and outdated software accumulates known vulnerabilities." Also, Peter Zaitsev warned in ITPro's article that the risks grow over time, "Over time, you limit your choices and see issues around performance or security." He added that "end of life software projects can be hard to get support for internally too," noting that keeping aging systems running often involves making changes with no performance improvements and real change management risk.

Compatibility starts breaking down

Zaitsev highlighted in the ITPro article that, "Those components might not run on newer hardware or on updated cloud infrastructure." You might start noticing emails that don't display correctly, attachments that won't open properly, or integrations with other tools that suddenly stop working.

Lenovo's endpoint security team also noted that aging software frequently causes instability that drives up helpdesk volumes, frustrates users, and quietly drains productivity.

There's also the vendor support angle, if you call your email software provider for help after end of life, they'll simply tell you that version is no longer supported.

Compliance problems

If your business operates under any kind of data protection regulation such as HIPAA, or industry-specific frameworks running unsupported email software can put you in direct violation of your obligations.

Regulations require organizations to maintain "adequate" or "reasonable" security measures. Continuing to use software that the manufacturer has declared unsafe by withdrawing support is a compliance liability. Regulators and courts tend to view it as negligence, and the fines and reputational damage that follow can exceed the cost of upgrading.

TechRadar Pro further warned that organizations still running unsupported software after EOL are likely to find themselves in violation of compliance standards that require current security patches and that cyber insurance policies may be voided entirely if an incident occurs on an unpatched, unsupported system.

So what should you actually do?

Middleton-Leal's advice from ITPro notes, "It's highly recommended adding mitigating controls around these applications to protect them". As Lenovo's endpoint security team put it, "Unsupported software won't fix itself."

• Find out where you stand. The first step is knowing what version of your email software you're running and what its end-of-life date is.
• Plan an upgrade path. Lenovo recommends a phased approach, prioritizing the highest-risk devices and applications first, rather than attempting a disruptive all-at-once overhaul.
• Don't wait for a crisis. The cost of a data breach, a compliance fine, or even just extended downtime outweighs the cost of a planned, managed upgrade.
• Budget for it properly. Building regular software lifecycle reviews into your annual planning makes it easier to budget for updates before they become emergencies. Lenovo's team notes that modern integrated IT solutions, when properly deployed, can actually reduce the operational drag caused by legacy systems.

FAQs

What is software end of life?

Software end of life is the point at which a vendor stops providing updates, security patches, and technical support for a product, leaving it vulnerable to emerging threats.

Is end-of-life software immediately dangerous?

Not immediately, but risk grows over time as new vulnerabilities are discovered with no patches coming to fix them.

What is the difference between end of life and end of support?

The terms are often used interchangeably, but end of support typically refers specifically to the cessation of technical assistance, while end of life refers to the complete retirement of the product.

Can I still use software after its end-of-life date?

Yes, the software will continue to function.