TL;DR
If your business phone system is a Mitel or Avaya premise PBX, “it still works” no longer means “it’s supported.” Mitel filed for Chapter 11 bankruptcy in March 2025 carrying $1.15 billion in debt, and its MiVoice Connect platform stopped receiving security patches entirely as of December 31, 2025. That’s not a future risk to plan around — for a lot of installed systems, it has already happened. The framework below scores exactly how exposed yours is.
The Status Quo Trap: “It still works, why touch it?”
Most IT leaders don’t replace a working PBX until it breaks. That instinct made sense when “still working” and “still supported” were the same thing. They aren’t anymore. A phone system doesn’t send an alert when its vendor’s patch pipeline goes dark, when the manufacturer files for bankruptcy protection, or when the last engineer who understood the on-prem hardware takes a job somewhere else.
Mitel — one of the largest installed bases of premise PBX hardware in North America — filed for Chapter 11 bankruptcy protection in March 2025 while carrying roughly $1.15 billion in debt. Its MiVoice Connect platform (formerly ShoreTel) stopped receiving security updates and OS patches as of December 31, 2025. MiVoice Office 250 support ends June 30, 2026. Neither date is a projection — both have already passed as of this writing, meaning any business still running those platforms today has zero vendor safety net if a vulnerability surfaces.
“It still works” was never actually the question that mattered. “Who fixes it when it doesn’t, and who patches it before that becomes a breach” always was.
The Tele Data Guru Framework: The Legacy PBX Exposure Score
Score your current system against four factors — any single “high risk” answer is reason enough to start planning a migration now, not at the next renewal:
| Exposure factor | Low risk | High risk — act now |
|---|---|---|
| Vendor solvency | Financially stable, actively developing the platform | Vendor in bankruptcy proceedings or has exited the market (e.g., Mitel’s March 2025 Chapter 11 filing) |
| Security patch cadence | Regular releases on a published support calendar | Patch support already ended (MiVoice Connect, Dec 31 2025) or ending within 12 months (MiVoice Office 250, June 30 2026) |
| Replacement hardware availability | Parts and refurbished units readily available from the manufacturer | Sourcing from a shrinking secondary/gray market, with longer outage windows when hardware fails |
| In-house platform expertise | Current staff trained and documented on the system | Knowledge held by one aging admin, or already walked out the door with a departed employee |
The True Cost of Standing Still
True Cost of Standing Still = (Annual Emergency Repair & Parts Spend) + (Probability of a Security Incident × Average Breach Cost) + (Opportunity Cost of Missing AI Coaching, Mobility & Omnichannel Features)
Most maintenance contracts on end-of-life hardware quietly bill full price for a shrinking pool of engineers who still know the platform — that line item alone often exceeds the cost of a modern per-seat UCaaS license before any breach risk or missed feature is even factored in. Add a single unpatched-vulnerability incident to that math, and the “it still works” system stops looking like the cheaper option.
Commercial Realities & Vendor Pitfalls
- “Rip and replace” is the story sold by whoever profits from you staying put. Most UCaaS migrations run in parallel with the existing system, with cutover and number porting handled after testing — not a weekend of dead phone lines.
- A bankruptcy filing doesn’t mean support stops overnight — but it does mean it stops being a priority. Check the actual published patch calendar for your specific hardware model, not a sales rep’s reassurance.
- Ask any UCaaS provider exactly how call transcription and AI coaching data is stored, and for how long. A genuine upgrade should tighten compliance, not just add features to a deck.
- Get the support team’s real staffing commitment in writing. An EOL maintenance contract can carry a full-price SLA backed by a shrinking, under-resourced support desk.
Implementation Checklist
- Score your current system against the Legacy PBX Exposure Score above.
- Pull the last 12 months of maintenance and repair invoices to calculate your actual “standing still” spend.
- Confirm your specific hardware model’s exact end-of-security-patch date directly with the manufacturer — timelines shift, and sales channels aren’t always current.
- Request a parallel-run migration plan from at least two UCaaS providers, not a rip-and-replace timeline.
- Pilot the new platform with one department or location before a full cutover.
- Revisit this scorecard annually — even platforms without a published EOL date today can change status quickly once a vendor’s financial position shifts.