Replacing old Avaya phones in 2026

Most UK SMEs retiring an Avaya estate in 2026 move to one of three routes: Microsoft Teams Phone, Zoom Phone or SIP desk phones on a hosted UC platform. Teams Phone suits firms already deep in Microsoft 365, Zoom Phone suits firms already built around Zoom, and hosted SIP suits anyone who wants a physical handset on the desk rather than a softphone on a laptop. This guide sets out who each route suits, what you need to run it and where it falls short.

The three routes

1. Move phone calls into your Microsoft 365 stack with Teams Phone. This suits firms already deep in M365.
2. Run calls through Zoom Phone. This suits firms already all-in on Zoom for meetings.
3. Fit dedicated SIP handsets on a hosted UC platform. This suits firms who want physical handsets on desks rather than softphones on laptops.

Most SMEs land somewhere on this spectrum rather than picking one route outright. Some run hosted UC for most people and keep a handful of desk phones for reception.

Microsoft Teams Phone

Teams Phone adds voice calling to the Teams app your staff already use. Calls run through the same Teams client your users already sign in to on a laptop, a mobile or a Teams-certified handset.

Who it suits

Firms already on Microsoft 365 Business Standard or Business Premium get the most value, especially if users are happy to take calls through a headset on a laptop rather than a physical desk phone. It also works well for businesses with staff spread across offices and home working.

What you need

You'll need a Teams Phone add-on licence per user, plus a calling plan or SIP trunk for outbound calls. Direct Routing, where you bring your own trunk, works out cheaper at volume, while Calling Plans are simpler to set up. Some firms add Teams-certified handsets on reception or shared desks, such as the Poly Edge E series, Yealink MP54 or MP58, or AudioCodes RX-series.

Strengths

• One tool, so users don't have to learn a new client.
• Strong presence and directory integration.
• Handles video, chat and screen-share in the same place as calls.

Drawbacks

• It needs stable internet, with no LAN-only fallback.
• Cost per user adds up on large estates.
• Admin tooling is Microsoft-native, so teams used to Google Workspace face a learning curve.

Zoom Phone

Zoom Phone brings voice calling into Zoom's platform, using the same client as your Zoom meetings but extended to phone traffic.

Who it suits

This route suits firms already using Zoom heavily who don't want to consolidate onto Teams. It also fits contact-centre-lite setups, where Zoom's queue management handles the load well.

What you need

You'll need a Zoom Phone licence per user and either a calling plan, metered or unlimited, or a bring-your-own SIP trunk, which Zoom calls Zoom Phone BYOC. Some firms add Zoom-certified handsets from Poly, Yealink or Grandstream, the same suppliers as Teams but on different firmware.

Strengths

• A simple admin console.
• Smooth transitions between meetings and calls.
• Fair pricing at small scale.

Drawbacks

• The ecosystem is narrower than Microsoft's.
• It's Zoom-centric, so moving off Zoom for meetings later means migrating the phone system too.

SIP desk phones on a hosted UC platform

This route puts physical desk phones on an internet connection, registered against a hosted phone platform such as RingCentral, 8x8, Vonage Business, GoTo Connect, Nextiva, Zoom Phone or Webex Calling. No PC is needed to make a call.

Who it suits

It works well for reception desks and shared spaces where a physical phone is the right form factor, and for businesses whose staff don't want to wear headsets. It also gives sites a working phone when the PC is off.

What you need

You'll need a hosted UC subscription, where plans vary by features and provider, plus SIP handsets such as the Yealink T5x series, Poly Edge, Grandstream GRP series or Cisco 88xx. Refurbished SIP handsets are readily available and cheap. Sites running many concurrent calls need a decent network connection with QoS.

Strengths

• A familiar desk-phone experience.
• The physical handset survives a laptop reboot.
• Refurbished handsets are readily available and cheap.

Drawbacks

• Two devices to manage per user, the phone and the PC.
• The network set-up matters more, including QoS, VLANs and PoE.
• There are more moving parts than a pure-software setup.

Handset rankings for 2026 SIP deployments

If you've settled on physical desk phones and need to specify models, these four tiers cover most hosted deployments.

The Yealink T33G, T43U and T46U are the solid entry choice. They have colour screens, gigabit ports and work with most hosted platforms out of the box. Refurbished units are easy to find, which keeps them affordable.

The Poly Edge E320 and E450 sit in the solid mid-range. They have a cleaner build than the Yealink models, better handset ergonomics and solid support on Teams-certified deployments.

The Cisco 8845 and 8865 sit at the enterprise tier. Build quality is higher and support is strong, though they cost more and often need a Cisco-certified admin.

The Grandstream GRP2612 and GRP2614 are the budget option. The firmware isn't as polished as Yealink's, but they're perfectly workable at the entry end.

Avaya J169, J179 and J189 handsets already sitting in a stock cupboard are worth checking before buying new. Avaya's SIG=SIP conversion lets many of them re-provision against hosted UC platforms. It isn't always plug-and-play, but it's doable.

Match by business shape

• Solicitors, accountants and small consultancies with 5-40 users tend to do well on Teams Phone with a couple of Poly desk phones on reception, a simple, familiar setup.
• A manufacturing SME with 20-60 users often runs hosted UC with Yealink desk phones on the shop floor, where physical handsets need to survive rough conditions, and Teams softphone for office-side staff.
• An independent hotel with 10-30 rooms usually needs a specialist migration. Wake-up calls, PMS integration and cost management mean this calls for advice specific to the hotel's PMS, not a generic recommendation.
• A multi-site SME with poor rural broadband often ends up with a hybrid setup: an on-prem PBX at the site with the reliable connection, and hosted UC everywhere else. Some Avaya IP Office estates stay in exactly this shape for another 3-4 years.

About your old handsets

Once you've picked a replacement, the old kit still needs to go somewhere. Some SIP handsets from your old estate can be reprovisioned. Digital Avaya handsets that only work with an Avaya PBX cannot come with you. Our guide to factory resetting old desk phones covers what to do before they leave your site.

Each handset we collect is cleared to factory defaults, logged by serial and model, and covered by a signed certificate. See What we buy: desk phones or drop us a note through the contact page.

See also: The PSTN switch-off explained · What to do with old Avaya digital phones in 2026 · Are old Avaya phones still useful in 2026?