Every operating system has a support lifecycle — Windows, macOS, and Linux alike. When support ends, security patches stop. And when patches stop, attackers pay attention. If your EOFY tech refresh doesn’t address unsupported systems across your entire environment, you’re buying yourself a breach.
It’s June. EOFY sales are everywhere. Your inbox is flooded with ‘last chance’ deals on laptops, monitors, and networking gear. The instant asset write-off is calling your name.
But before you click ‘buy now’ on that suspiciously cheap laptop or clearance-priced router, ask yourself one question: will this equipment run secure, supported software for the next three to five years?
Because in 2026, the wrong tech purchase isn’t just a bad investment — it’s an open invitation to attackers. Legacy systems are now the number one infrastructure risk facing Australian businesses, and this applies whether you’re running Windows PCs, Macs, Linux servers, or a mix of all three.
The Legacy Technology Crisis in Numbers
The data on outdated technology is sobering — and it applies across platforms:
- 59% of Australian organisations report that legacy IT is blocking their ability to implement Essential Eight security controls
- 71% increase in attacks on unsupported systems within six months of end-of-life — regardless of platform
- 43% of Australian breaches in 2024 had outdated software as a contributing factor
- macOS vulnerabilities doubled in 2024 compared to 2023, with 69 actively exploited in the wild
- Linux servers running EOL distributions accounted for 14% of ransomware entry points in APAC
- 8.5% of Windows systems are still running Windows 7 — end-of-life since January 2020
The ASD’s Annual Cyber Threat Report now explicitly lists ‘replace legacy IT’ as one of the four big moves businesses should make to protect themselves. This isn’t platform-specific guidance — it applies to your entire technology stack.
The Support Lifecycle Reality: Every Platform Has an Expiry Date
There’s a common misconception that Macs ‘don’t get viruses’ or that Linux is inherently secure. The reality is more nuanced: every operating system requires ongoing security patches, and every platform eventually reaches end-of-life.
Windows: The October 2025 Cliff
Windows 10 reached end-of-life on October 14, 2025. Eight months later, it no longer receives security patches, yet 38% of Australian PCs still run it. Windows 11 requires specific hardware (TPM 2.0, compatible CPU) that older machines don’t have. If your Windows PCs can’t upgrade to Windows 11, they need replacement.
macOS: The Rolling Cutoff
Apple typically supports the current macOS version plus two previous versions with security updates. As of June 2026, this means Sequoia (15), Sonoma (14), and Ventura (13). If you’re running Monterey (12) or older, you’re no longer receiving security patches. Apple’s hardware requirements also mean older Macs simply can’t run current macOS — a 2017 MacBook Pro, for instance, can’t run anything newer than Monterey.
Linux: Distribution Matters
Linux security depends heavily on distribution and version. Ubuntu LTS releases receive security updates for 5 years (10 with extended support). CentOS 7 reached end-of-life in June 2024. Debian 10 is no longer supported. Many businesses running Linux servers deployed them years ago and haven’t tracked support timelines — those servers may now be unpatched and vulnerable.
The ‘Macs Don’t Get Viruses’ Myth
This was never true, and it’s dangerous in 2026. macOS vulnerabilities have surged as Apple’s market share has grown. In 2024, 69 macOS vulnerabilities were actively exploited. Malware like MacStealer, Atomic Stealer, and various adware strains specifically target Mac users. An unsupported Mac running outdated macOS is just as vulnerable as an unsupported Windows PC.
Five Ways Outdated Technology Puts You at Risk
1. No Security Patches = Open Season for Attackers
When any operating system reaches end-of-life, new vulnerabilities stop being fixed. But they don’t stop being discovered. Security researchers — and criminals — continue finding flaws. The difference is that now those flaws remain permanently exploitable. This applies equally to Windows, macOS, and Linux.
2. Compliance Failures and Regulatory Risk
Running unsupported software can breach Australian Privacy Principles, industry regulations, and frameworks like ISO 27001. Regulators don’t care what operating system you use — they care whether it’s supported and patched. Cyber insurance policies increasingly exclude coverage for incidents involving unsupported software on any platform.
3. Legacy Systems Can’t Run Modern Security Tools
Modern endpoint protection, zero-trust architectures, and security monitoring tools require current operating systems. If your Mac can’t run Ventura or your Linux server is on CentOS 7, you’re locked out of modern defensive capabilities. You’re not just missing patches — you can’t deploy current security tools.
4. The Mixed Environment Challenge
Many businesses run a mix of platforms — Windows for most staff, Macs for creative teams, Linux for servers. This is completely valid, but it means security must span all platforms. One compromised Mac on your network can become a beachhead to attack Windows systems. One unpatched Linux server can expose your entire infrastructure.
5. Hidden Costs Add Up
Legacy systems require more maintenance, more workarounds, and more IT time — regardless of platform. That old Mac running Catalina can’t use current versions of Creative Cloud. That Linux server on an EOL distribution requires manual security monitoring. The ‘savings’ from not upgrading often cost more than replacement would have.
The Full Cross-Platform Audit
When planning your EOFY refresh, audit your entire technology environment:
Windows Devices
- Identify all devices still running Windows 10 or older
- Check Windows 11 compatibility (TPM 2.0, supported CPU)
- Plan upgrades or replacements for incompatible hardware
Mac Devices
- Identify all Macs running Monterey (12) or older
- Check Apple’s compatibility list for current macOS support
- Budget for replacement — older Macs can’t be upgraded to supported versions
Linux Systems
- Identify distribution and version for all Linux servers and devices
- Check support timelines — CentOS 7, Debian 10, Ubuntu 18.04 are all EOL
- Plan distribution upgrades or migrations to supported versions
Network Equipment
- Routers, firewalls, and switches older than 5-7 years often lack firmware updates
- Check vendor support lifecycle — this is platform-agnostic
- Replace EOL network equipment regardless of what computers connect to it
Mobile Devices
- iPhones: Apple typically supports devices for 5-6 years
- Android: Support varies by manufacturer, typically 3-4 years for security updates
- Check whether devices can run current OS versions with security patches
Your EOFY Tech Refresh Checklist
Before you buy anything this EOFY, use this framework:
Before Purchasing
- Audit current equipment — identify everything running unsupported software across all platforms
- Check compatibility — can existing hardware upgrade to current operating systems?
- Verify vendor support lifecycles — how long will new equipment be supported?
- Choose the right platform — match device type to user needs and business requirements
- Plan for disposal — secure data destruction methods differ by platform
When Purchasing
- Choose business-grade equipment — whether Windows, Mac, or Linux, business-grade means better support
- Verify current OS support — Windows 11 compatible, supports current macOS, or current Linux distro
- Consider total cost of ownership — including cross-platform management and security tools
- Buy from reputable vendors — grey-market equipment may lack warranty and support
- Document everything — serial numbers, warranties, support contacts for all platforms
After Purchasing
- Secure configuration — Windows, macOS, and Linux each have platform-specific hardening requirements
- Install endpoint protection — cross-platform security suites protect your mixed environment
- Enable automatic updates — on all platforms: Windows Update, macOS Software Update, apt/yum
- Configure MFA — before any device connects to business systems, regardless of platform
- Securely dispose of old equipment — Macs require different procedures than PCs; use certified destruction
A Cautionary Tale: The Mixed Environment Breach
A Brisbane design agency learned this lesson in early 2026. Their creative team ran Macs; admin staff used Windows; their file server ran Ubuntu. They’d upgraded the Windows machines to Windows 11 but assumed the Macs and Linux server ‘were fine.’
One designer’s 2016 MacBook Pro was still running macOS Monterey — no longer receiving security updates. The Linux server was running Ubuntu 18.04, which reached end-of-life in April 2023. Both had known, unpatched vulnerabilities.
Attackers compromised the Mac first through a Safari vulnerability. From there, they moved laterally to the Linux file server, exploiting an unpatched privilege escalation bug. They exfiltrated client design files and demanded ransom.
The fallout:
- Client files for 23 projects compromised
- Mandatory breach notification to affected clients
- Two weeks of downtime while systems were rebuilt
- Lost client contracts worth $180,000
- Emergency replacement of all unsupported equipment
The breach path went Mac → Linux → client data. Upgrading only their Windows machines wasn’t enough. Security requires covering your entire environment.
Special Considerations for Healthcare Providers
Medical practices often run mixed environments — Windows for admin, sometimes Macs for practitioners, Linux for specific applications. Key considerations:
- Practice management software compatibility — verify your PMS supports current OS versions on your platform
- Medical device integration — some diagnostic equipment requires specific OS versions
- My Health Record requirements — ADHA security standards require current, supported systems
- Platform-specific secure disposal — patient data must be securely erased using correct procedures for each device type
- Cross-platform endpoint protection — security solutions that cover Windows, Mac, and any Linux systems
Five Things You Can Do in the Next 30 Minutes
- Check your Windows devices — run Microsoft’s PC Health Check to identify Windows 11 compatibility
- Check your Macs — click Apple menu > About This Mac to see your macOS version
- Check your Linux servers — run ‘lsb_release -a’ or ‘cat /etc/os-release’ to identify distribution and version
- Check your router’s age — if it’s more than five years old, add it to the replacement list
- Contact your IT provider — get a professional cross-platform assessment before EOFY purchases
Why Cross-Platform Expertise Matters
Many IT providers only support Windows. That leaves businesses with Macs or Linux systems scrambling for separate support — or worse, leaving those systems unmanaged and vulnerable.
At Kalluri IT, we support Windows, macOS, and Linux. Your creative team’s Macs, your admin staff’s Windows PCs, your Ubuntu servers — we manage security across your entire environment. No gaps, no excuses, no ‘that’s not our department.’
Because attackers don’t care what platform you run. They care about finding the weakest link — and that link could be on any operating system.
Make This EOFY Count
The equipment decisions you make this month will shape your security posture for years. At Kalluri IT, we’ve been helping Australian businesses make smart technology investments since 2012 — supporting Windows, macOS, and Linux across healthcare, legal, and professional services.
Our EOFY Tech Refresh Service includes:
- Complete cross-platform device and software audit
- OS support status assessment — Windows, macOS, and Linux
- Network equipment lifecycle review
- Prioritised replacement recommendations for all platforms
- Secure deployment and platform-appropriate configuration
- Certified data destruction for retiring equipment — any platform
Don’t let a bargain become a breach — on any platform.