At a glance
Major PBX lifecycle dates
A vendor announcement can apply to a release, licensing model, or entire product family. Verify the exact release and support contract before making a budget decision.
| Platform | Milestone | Date / status |
|---|---|---|
| Avaya Aura Platform R10.1 | End of manufacturer support | January 1, 2026 |
| Avaya G430 / G450 gateways, older vintages with Aura 10.2 | End of manufacturer support | June 30, 2026 |
| ShoreTel 14.2 | End of life | September 2020 |
| Mitel MiVoice Connect | End of Technical Support | December 31, 2029 |
| Mitel MiVoice Office 250 | Core technical support / Application Suite support | June 30, 2026 / June 30, 2027 |
| Cisco CUCM 12.5 subscription | Last date of support | August 31, 2025 |
| Cisco CUCM 14 perpetual | Software maintenance / last support | April 7, 2026 / April 30, 2027 |
| Cisco UCCX / UCCE / PCCE / CVP 12.5–12.6 | Software maintenance / last support | December 31, 2026 / December 31, 2027 |
| Genesys Engage / PureEngage premises | All renewals close / maintenance and support end | November 30, 2028 / December 31, 2028 |
| Nuance Recognizer / Vocalizer speech engines | Expansions closed / end of manufacturer support | June 30, 2025 / June 30, 2026 or June 30, 2027, by license term |
| NEC UNIVERGE on-premises UC | New system sales ended outside Japan; Americas business transferred | Transition began in 2024–2025; confirm platform entitlement |
| Skype for Business Server 2015 / 2019 | End of support; final paid ESU period | Support ended October 14, 2025; ESU ends October 2026 |
| Copper POTS lines (carrier-dependent) | Grandfathering and discontinuance | No national date, AT&T has requested discontinuance on or after November 15, 2026 |
Primary sources include Mitel’s ShoreTel product history, Mitel’s MiVoice Office 250 lifecycle guidance and a copy of Mitel bulletin PB2021Apr5A, Cisco’s CUCM 12.5, CUCM 14, and on-premises contact-center 12.5/12.6 bulletins, plus the Genesys Engage EOL announcement. NEC dates and entitlements vary by region and successor support arrangement.
Read the fine print
“End of life” is not one event
End of sale
New licenses or systems stop selling. Existing support may continue for years, but expansion can become difficult.
End of software maintenance
Engineering stops regular bug fixes and maintenance releases. Security exposure becomes the bigger concern.
End of renewals
You can no longer extend the vendor contract beyond a specified date, even if the system still runs.
Last date of support
Vendor TAC and entitled services end. After this date, the product is operationally yours alone.
Your paths
Four realistic replacement strategies
- Upgrade on premises. Best when you have hard local-survivability, compliance, or customization requirements and a vendor still offers a supported release.
- Move business calling to UCaaS. Replaces PBX call control with a cloud service such as Teams Phone, Webex Calling, RingCentral, Zoom Phone, or 8x8.
- Separate UCaaS and CCaaS. Keep employee calling simple while moving queues, WFM, recording, and digital channels to a dedicated contact-center platform.
- Use third-party support as a bridge. Useful for a dated transition window; it does not restore vendor engineering, future integrations, or product strategy.
Before an RFP
The PBX exit checklist
- Export users, DIDs, hunt groups, IVRs, schedules, prompts, and call-flow diagrams.
- Inventory fax, elevators, alarms, paging, door phones, modems, and other analog lines.
- Document 911 location requirements and branch survivability.
- Separate employee calling seats from true contact-center agents.
- Test CRM, recording, compliance, and reporting requirements with real workflows.
- Plan number ports in waves and keep rollback routing available.
Platform guides
Check your exact system
The do-nothing budget
What staying on an unsupported PBX actually costs
Running past a support deadline is a decision with its own budget line, not a default. What changes is who fixes the system, what parts cost, and how much risk you quietly absorb.
Third-party support fees
Independent maintainers will cover an EOL PBX, often below the vendor’s last renewal quote. Read the scope: most contracts cover break/fix and troubleshooting, not security patches or engineering escalation.
Parts and handset scarcity
After production ends, spares come from refurbishers and the secondary market. Controllers, gateway cards, and power supplies get scarce first, so one failed component can become a multi-week outage.
Security and compliance exposure
No maintenance releases means known vulnerabilities stay open. A phone platform that touches cardholder or patient data tends to surface as an audit finding under PCI, HIPAA, or state privacy rules.
Insurance questionnaires
Cyber-insurance renewals increasingly ask about unsupported or end-of-life software. A yes can mean higher premiums, compensating controls, or coverage exclusions; an inaccurate answer risks a denied claim.
Added up honestly, the “free” years on a paid-off PBX often cost more than the first years of a replacement.
Plan backward
A phased migration timeline
Work backward from the support end date and leave slack at the finish. A simple single site fits in 6–12 weeks; multi-site or contact-center-heavy environments should plan 3–9 months. The phases are the same either way, the durations stretch.
- Inventory and discovery (1–3 weeks). Export everything in the checklist above, users, numbers, call flows, analog dependencies, integrations, contract dates. Every later phase depends on it.
- Requirements, split UC from contact center (1–2 weeks). Sort every seat into “employee calling” or “agent.” The two lists price and shortlist differently, and can go to different vendors.
- Shortlist and quotes (2–6 weeks). Run three or four vendors against comparably scoped requirements. Demos on your real call flows beat feature checklists.
- Contract and legal (1–4 weeks). Negotiate term, seat counts, implementation credits, and price locks. Don’t start the porting clock until signatures are done.
- Build, port, and cutover (2–8 weeks). Configure and test, then port numbers in waves with rollback routing held open. Cutting over wave by wave is what stretches large projects into months.
Phases overlap in practice, but porting is the immovable step: carrier port dates slip, so never schedule a cutover against a hard deadline with no buffer.
Money
Budget factors for the replacement
Replacement budgets go wrong in the same few places: usage, add-ons, and one-time work hiding behind the visible seat price.
- Contact-center seats. Most contracts land between $50 and $110 per agent per month, roughly $70–$95 for full omnichannel, $95–$110 with AI and workforce suites. Only true agents need these seats.
- Employee calling seats. UCaaS seats cost far less than agent seats, splitting the two populations is the biggest single lever on the total.
- Telephony usage. Some providers bundle domestic minutes; others meter everything. Heavy outbound or international traffic can add 20–40% at metered rates.
- Modules and add-ons. Workforce management and quality management typically run $10–$40 per agent; AI is bundled, per-seat, or usage-priced depending on the platform.
- One-time work. Implementation, IVR builds, and migration services run from a few thousand dollars to five figures, plus network readiness and any handset refresh.
- Negotiation. List prices are a starting point, deals routinely close 15–30% below list with competing quotes and term trades.
Where to go next
Build the replacement shortlist
The fastest way to shrink a vendor list is the UC-versus-CC split from phase two. Most employees need a dependable calling seat. Seats that answer queues need routing, callbacks, recording, and workforce tools, a different product category. New to it? Start with what CCaaS is and the CCaaS pricing guide.
Organizations standardized on Microsoft 365 often keep calling in Teams and add a Teams-based contact center for the queues. For one vendor and one bill covering both sides, look at bundled options like RingCentral RingCX. When the contact center is the demanding half, shortlist dedicated platforms such as Five9 and Genesys Cloud.
FAQ
Quick answers
Can an EOL PBX keep working?
Yes. The risk is that recovery, patching, parts, expansion, and vendor escalation become less predictable precisely when you need them.
Should we replace the phones too?
Not automatically. Some SIP devices can be reused, but old firmware, proprietary features, and poor cloud provisioning may make reuse costlier than a staged refresh.
How long should we allow?
Allow 6–12 weeks for a simple site and 3–9 months for multi-site or contact-center-heavy environments.
Is third-party support a safe long-term plan?
It’s a bridge, not a destination. Independent support keeps an EOL PBX running but cannot ship security patches or restore vendor engineering. Set an exit date before you sign, and treat the savings as migration budget.
What will a replacement cost?
Cloud contact-center seats mostly land between $50 and $110 per agent per month, and employee calling seats cost well under that. Add one-time implementation from a few thousand dollars to five figures. Competing quotes routinely close 15–30% below list.
Do we have to move every site at once?
No. Most multi-site migrations run in waves, a pilot site first, then groups, with rollback routing held open. UC and the contact center can also move on separate timelines.