Is your business phone system still supported?
What's changed at Avaya and Mitel
Both vendors have been through Chapter 11, and several of the platforms UK businesses run every day are now past end of support. This guide sets out what has actually changed, what it means for your system, and what your options are. Every claim is referenced.
No obligation. We'll tell you where your system stands even if you don't move to us.
What this guide covers
- 01Where your platform stands
- 02What we do differently
- 03How a migration works
- 04The eight questions we get asked
Written by the Zen Systems team, a 3CX Titanium Partner with 18+ years of experience.
What actually changed
Two vendors. Two bankruptcies. What it means for your system
We're not here to knock the kit: much of it ran faithfully for fifteen years. But the commercial reality has moved, and if you're an IT manager being asked to justify a change, these are the facts you can take to your board. Every claim below is sourced.
Avaya
Filed Chapter 11 in February 2023 and emerged in May 2023, its second filing in six years.3- Has publicly pivoted to large enterprise, and as of 30 June 2025 discontinued support for contact centres under 200 seats.3
- A phase-out of selected services (including SIP trunking and CPaaS) took effect from April 2025.4
- IP Office R11.1 and earlier now sit in a reduced-support window with limited or no software patch availability.3
If you're an SME or a sub-200-seat contact centre, you are no longer the customer Avaya is building for. That's a strategy decision, not a reflection on you.
Mitel
- Filed a prepackaged Chapter 11 on 10 March 2025 and emerged on 20 June 2025, now owned by its former lenders.1
- The restructuring cut around $1.15bn of debt after a period that included divesting its UCaaS business.2
- Two of its most widely installed on-premises platforms (MiVoice Connect and MiVoice Office 250) are past or at full end of support.5
- MiCloud Connect shut down permanently on 24 June 2026.6
Mitel is trading and MiVoice Business has no published end-of-life date. But its platforms are now on very different clocks, and you need to know which one you're on.
Find your system
Where does your platform stand?
Published lifecycle milestones for the platforms we're most often asked to replace. Find yours, then tell us the release you're on and we'll confirm it against the vendor's own notice before anyone commits to anything.
Mitel platforms4 platforms
MiVoice Office 250
Formerly Inter-Tel 5000 / Mitel 5000
30 June 2026
Past deadlineEnd of all technical support. New system sales ended January 2022, add-on sales June 2022 and software design support January 2023.5
MiVoice Connect
Formerly ShoreTel
31 December 2025
Past deadlineEnd of security patches and OS updates, now maintenance-only. Hardware repair support runs to 31 December 2028 and all support ends 31 December 2029.5
MiCloud Connect
Mitel's former public cloud UCaaS
24 June 2026
Past deadlineShut down permanently. If you were on this platform you have already had to move: the question is whether you moved to something you actually chose.6
MiVoice Business
3300 ICP platform
No published EOL
SupportedMitel's stated go-forward on-premises platform with no announced end-of-life date. If it's working and your partner relationship is healthy there's no technical emergency, but it's worth knowing where you stand all the same.5
Avaya platforms4 platforms
IP Office R11.1 and earlier
R11.0, R10.x, R9.x and older
Reduced support window
Reduced supportOlder releases are losing software patch and security support. Licensing and upgrade rights are tied to where your release sits in Avaya's rolling support model.3
IP Office R12.0
Current release family
No published EOL
SupportedStill commercially available and supported on current releases, but the strategic direction of travel for sub-200-seat businesses is set, even without a formal EOL date.3
Public cloud contact centre
Deployments under 200 seats
30 June 2025
Past deadlineAvaya discontinued direct support for public cloud contact centre deployments with fewer than 200 seats, as part of its stated focus on large enterprise.3
Selected Avaya services
Including SIP trunking and CPaaS
From April 2025
Past deadlineA gradual phase-out of selected services took effect, alongside organisational restructuring to support the new enterprise-first direction.4
Dates are as published by the vendors and their partner channels at the time of writing, see sources. Lifecycle notices do change. We verify your specific platform, release and licence position in writing as step one of every migration.
How we're different
What a specialist does that a global vendor doesn't
Avaya and Mitel build platforms and sell them through a channel. We design, host and support yours ourselves: one company, one number to call, and a business that is 100% telecoms.
One company owns the whole thing
Total control of the design, setup, hosting and support of your 3CX system. No passing the parcel between a vendor, a reseller and a hosting provider when something needs fixing.7
You're the size of customer we're built for
Avaya has publicly refocused on 200-seat-plus enterprise.3 SMEs, IT managers and sub-200-seat contact centres are our core business, not a segment being managed out.
Reducing your costs is written into the deal
A fixed system price with additional users at no extra cost, your 3CX licence included, inclusive UK landline and mobile minutes, cloud backups and 24/7 monitoring, and a guarantee to reduce your costs wherever possible.7
Why Zen Systems
We know how it feels. We've done this hundreds of times
Running a business is hard enough without your phones being a worry. We're a 100% telecoms-focused 3CX Titanium Partner with 18+ years of experience, and we've successfully migrated hundreds of businesses over that time. We host your system ourselves, so when something needs attention, you talk to the people who built it.
3CX Titanium Partner
18+ years of experience and a Titanium partner ID of 202649. We've been specialists in it since 2007.
Our own private cloud
Hosted on our private cloud in Equinix's London data centres, with a 99.99% uptime SLA, cloud backups and 24/7 monitoring.
Support you can actually reach
Unlimited support by phone, email and live chat, and rated Excellent on Trustpilot. Hundreds of long-standing customers.
Total Peace of Mind guarantee
A reliable service with a 99.99% uptime SLA, exceptional support, a service that meets your needs, and reduced costs wherever possible.
Your plan
The 4-Step Easy Migration Plan
The same proven plan we've used to move hundreds of businesses for 18+ years. We guide you every step of the way, and we switch you over without downtime.
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1
Discovery
We understand your current phone system, your needs and your challenges, including exactly which release and licences you hold.
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2
Design
We craft a custom solution: features, configurations and integrations mapped against what you have today, feature by feature.
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3
Prepare
We set up SIP trunks, private cloud hosting, number ports and team training, while your old system keeps running.
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4
Switch
We manage the migration, switching you over without downtime, with ongoing support from the moment you go live.
Straight answers
The eight things people ask us first
Every one of these is a fair question. Where the answer is "it depends on your site", we say so rather than promise something we haven't checked.
"A migration will cause downtime."
We build and configure your new system in parallel while your existing one keeps running, then manage the switch itself: our plan is designed to move you across without downtime.
"We'll lose our phone numbers."
You keep them. Number porting is part of the Prepare step and we handle it for you. Your stationery, your website and your Google listing all stay exactly as they are.
"Our handsets become landfill."
We audit your handset estate during Discovery and tell you in writing which models can carry over and which can't, before you commit to anything. We won't guess at that on a web page.
"Our staff will have to relearn everything."
Team training is built into the Prepare step, before go-live. Customers consistently describe 3CX as user-friendly.
"Contact centre features won't match."
We map your queues, routing rules, wallboards, recording and reporting against 3CX feature by feature during Design, and we tell you honestly where there's a gap rather than discovering it at go-live.
"We have DECT, paging, door entry and alarm lines."
So do most sites we move, and they are exactly the details that get missed. Discovery audits every line and every attached device: lifts, alarms, door entry, paging, fax, card terminals, so nothing is found on switch day.
"We're mid-contract."
Tell us your renewal date and we'll plan backwards from it. Knowing your notice period early is worth far more than discovering it late, and the design work can start well before you switch.
"Zen is smaller than Avaya or Mitel."
We are, and that's rather the point of this page. We've been trading since 2007, we're 100% telecoms focused, we own the cloud your system runs on, and you can get a human on the phone.
Proof
People who've already made the move
A 40-user accountancy firm, mid-contract and out of support
A representative example of the migrations we're asked for most often, anonymised at the client's request.
- 01Legacy on-premises PBX with ISDN30 termination, no longer receiving software updates, plus a paging system and two alarm lines nobody had documented.
- 02Discovery mapped every line and attached device, and the existing call flows and reporting requirements, before any hardware was quoted.
- 033CX on Zen's private cloud, numbers ported, staff trained ahead of go-live, and the switch itself completed without downtime.
Trusted by UK businesses
Don’t just take our word for it
Businesses across the UK rate Zen Systems Excellent on Trustpilot.
A breath of fresh air
“Compared to anyone else I have previously used they are like a breath of fresh air! James, Dean and the team have been great getting this excellent, feature-rich system up and running. I would highly recommend them.”
Very pleased with the new system
“We had problems with BT and were recommended to Zen Systems for our digital phone upgrade. James and his team helped us implement 3CX and it is very user-friendly. Their support is very helpful and resolves any issues quickly.”
Very knowledgeable 3CX service provider
“Zen Systems demonstrated very clearly their expertise with 3CX. James Howard-Dobson and his team were extremely helpful in migrating us from our previous provider. I am pleased to report our service is now running very smoothly.”
Find out exactly where your system stands
One conversation with a 3CX migration specialist. We confirm your platform, release and licence position against the vendor's own lifecycle notice, review your lines and attached devices, and tell you what your options actually are, whether or not you move to us.
Backed by the Zen Systems Total Peace of Mind service guarantee.
Sources & citations: 7 sources
- Mitel, Financial Restructuring: restructuring completed effective 20 June 2025; ownership transitioned to its lenders.
- Court and adviser records of Mitel's prepackaged Chapter 11 (filed March 2025, emerged 20 June 2025), reporting debt reduced by approximately $1.15bn.
- Independent partner analysis of Avaya's position (Chapter 11 February–May 2023; pivot to 200+ seat enterprise; contact centre support under 200 seats discontinued 30 June 2025; IP Office R11.1 and earlier in reduced-support window).
- Partner reporting on Avaya's phase-out of selected services, including SIP trunking and CPaaS, from April 2025.
- Mitel lifecycle documentation as reported by Mitel partners: MiVoice Office 250 end of technical support 30 June 2026; MiVoice Connect end of security patches 31 December 2025, hardware repair to 31 December 2028, all support ending 31 December 2029.
- Reporting on the permanent shutdown of MiCloud Connect on 24 June 2026.
- Zen Systems' own published claims: 18+ years of experience, Titanium Partner ID 202649, Equinix London private cloud, 99.99% uptime SLA, Total Peace of Mind guarantee.
Lifecycle dates are as published at the time of writing and are subject to change by the vendors. Nothing on this page should be read as a statement made by Avaya or Mitel.