If your enterprise is running a legacy PBX — Avaya, Cisco, or Mitel — you're closer to a forced migration than you might think. This guide covers the end-of-life landscape, your options, and how to plan a migration that doesn't disrupt your business.
1. The PBX end-of-life landscape (2026)
The three major enterprise PBX vendors are all in different stages of end-of-life. Here's where each stands:
Avaya Aura 10.1 — End of support: January 2026
Avaya's second bankruptcy restructuring has shifted the company's focus to cloud CX platforms. Aura 10.1, the current on-prem release, reaches end of support in January 2026. After that: no security patches, no bug fixes, no vendor support.
Mitel MiVoice Connect — End of sale, Chapter 11
Mitel filed Chapter 11 in March 2025 and has aligned strategically with Zoom. MiVoice Connect reached end of sale in December 2025. MiCloud Connect reaches end of life in June 2026.
Cisco CUCM — Active migration recommendation
Cisco is actively recommending cloud migration for CUCM customers. While CUCM isn't end-of-life, Cisco's roadmap prioritizes Webex Calling and cloud-based UC over on-prem CUCM.
2. What PBX end-of-life means for your enterprise
End-of-life isn't just a vendor support issue. It creates a cascade of risks:
- No security patches — new vulnerabilities go unaddressed
- No vendor support — when something breaks, you're on your own
- Compliance gaps — E911 requirements tighten; unsupported PBXs can't keep up
- Hardware failure risk — replacement parts become scarce
- Talent drain — engineers leave for modern platforms; hard to replace
3. Your migration options
Three paths lead to Teams Phone. The right one depends on your size, complexity, and analog dependencies:
- Microsoft Calling Plans — easy to deploy, but expensive at scale ($12–24/user/month on top of Teams Phone). No analog support.
- Operator Connect — simpler than Direct Routing, but no analog device support and limited custom routing.
- Direct Routing via SBC — the enterprise path. Full control, analog integration, cost savings of up to 60%, E911 compliance engineered in.
4. Why Direct Routing is the right path for enterprises with legacy infrastructure
If you have analog devices — elevator phones, paging systems, fax machines — Direct Routing is your only viable option. Calling Plans and Operator Connect simply cannot integrate analog devices. Direct Routing via SBC handles:
- Analog device integration through ATAs
- Protocol translation (H.323/SCCP → SIP)
- Dial-plan preservation and translation
- E911 compliance with PIDF-LO dynamic location routing
- Cost arbitrage vs Calling Plans (up to 60% reduction)
5. How to plan your migration timeline
Start 6–12 months before your vendor's EoL date. A typical engagement:
- Discovery (2–3 weeks) — Full audit of voice infrastructure, dial plans, analog lines, compliance status
- LLD & Lab (3–4 weeks) — Low-level design, SBC configuration, lab validation
- Pilot (2–3 weeks) — Production pilot with a subset of users, analog testing, E911 validation
- Production (1–2 weeks) — Full cutover, number porting, PBX decommission
- Hypercare (2–4 weeks) — Post-cutover monitoring, issue resolution, stabilization
6. The cost of waiting
Waiting until the EoL date forces an emergency migration under pressure — with less negotiating leverage, compressed timelines, and higher risk. You also face compliance exposure: unsupported voice infrastructure can't meet evolving E911 requirements. Plan now, on your timeline.
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