What Is Actually Happening
There is no single dramatic announcement here, which is exactly why so many businesses have missed it. What has happened instead is a series of individual product decisions, each communicated to the customers of that product, that add up to a pattern: the phone products Telstra sold to small and medium businesses in the 2010s are being wound down, one at a time.
Telstra has not published a statement describing this as an exit from small business voice, and it would be unfair to characterise it as abandonment — every one of these products has a migration path onto something else, and legacy platforms genuinely do reach the end of their useful life. But the practical effect for a business owner is the same regardless of how it is framed. A system you bought as a ten-year decision is now a countdown.
Read this the right way
This is not an argument that you must act this week, and it is definitely not an argument that Telstra is a bad carrier. It is an argument about sequencing. A migration you plan across six months is a routine project. The same migration compressed into six weeks because a disconnection date arrived is where businesses lose numbers, lose call history, and pay premium rates for whatever can be installed fastest. The only variable you control is when you start.
One important caveat before the dates. Several of the figures below have been reported by industry sources and integrators rather than announced in a single consolidated Telstra release, and product roadmaps change. Treat the table as a prompt to go and check your own account notices, not as a substitute for them. Where a date matters to a decision you are about to make, confirm it with your provider in writing.
The Reported Timetable
Two dates matter for any product being retired, and people routinely confuse them. Stop-sell is the date the product can no longer be bought or, usually, materially changed — the service keeps running, but it is frozen. End-of-service is the date it stops working. Stop-sell is the warning. End-of-service is the wall.
| Product | Closed to new customers | Stop-sell | End of service |
|---|---|---|---|
| Telstra Calling for Office 365 (TCO365) | 1 November 2024 | 30 August 2026 | 30 November 2026 |
| Telstra DOT (Digital Office Technology) | — | 30 September 2025 | 30 August 2027 |
| Telstra Business SIP | — | 30 May 2025 | Not publicly stated |
| Telstra ISDN (for reference) | June 2018 cease-sale | — | 31 May 2022 — complete |
Nov 2026
Reported withdrawal of Telstra Calling for Office 365 — the nearest hard date
Aug 2027
Reported end of service for Telstra DOT
May 2025
Business SIP stop-sell — existing services frozen since
4 years
How long the ISDN wind-down took from cease-sale to final disconnection
Notice the shape of that table. Business SIP is the interesting one, because it has no published end-of-service date at all. A product that cannot be bought, cannot usually be expanded, and has no stated end date is not a stable platform — it is a product in a holding pattern. If your business is growing and your voice service is frozen, the freeze itself is the problem, whatever the eventual disconnection date turns out to be.
Which Product Are You Actually On?
A surprising number of business owners cannot answer this, and that is not a failure of attention. These products were often sold years ago, sometimes by a dealer rather than Telstra directly, sometimes bundled with internet and mobiles on a single account. The phone on the desk says Telstra, the bill says Telstra, and the product name is buried in a line item.
Here is how to work it out from what is in front of you.
Start with the bill, not the hardware
Find the itemised service lines rather than the summary total. Legacy voice products appear under their product name — look for DOT, Digital Office Technology, Business SIP, SIP Connect, or a Microsoft-related calling line. The summary page will just say “voice”, which tells you nothing.
DOT has a distinctive footprint
DOT was sold as an all-in-one: a supplied gateway or modem, supplied handsets, and the phone service delivered over that same connection. If there is a Telstra-branded box that both the internet and the phones plug into, and you did not choose the handsets separately, DOT is the likely answer.
Business SIP sits behind a phone system
Business SIP is trunking, not a phone system. It feeds an on-premise PBX or an IP phone system you own. If there is a PBX in a comms cupboard and Telstra provides the lines into it, that is the pattern — and how SIP trunking works explains the architecture.
TCO365 shows up in Microsoft, not on a desk
If your staff make and receive external calls from inside Microsoft Teams and Telstra supplies the calling, that is Telstra Calling for Office 365. There may be no desk phones at all. This is the product with the nearest reported end date.
Check your account notices
Retirement notices are sent to the billing contact, who is frequently a bookkeeper or a former employee. Search the mailbox that receives the invoices for the product name. “Nobody told us” and “the notice went to an inbox nobody reads” look identical from the outside.
Or just ask, in writing
Ask your account manager two questions by email: which voice product is this service, and what is its published end-of-service date? Get it in writing. A verbal “you will be fine” is not a date, and the written answer is what lets you plan.
What ISDN Taught Us About Waiting
Australia has already run this exact experiment, at national scale, and the results are worth knowing before you decide to deal with it later.
ISDN was the business telephony standard for two decades. Telstra ceased selling it in June 2018, began disconnections in September 2019, and the final services came off on 31 May 2022. That is close to four years of notice — a generous runway by any measure.
And yet the pattern repeated in business after business. Nothing happened for two years, because nothing needed to. Then a disconnection notice arrived with a date on it, and a project that should have taken a quarter got compressed into weeks.
What the compression actually cost
Three things went wrong, over and over. Porting queues. Everyone in a region migrates at once, and number porting is a regulated process with real timeframes — you cannot buy your way to the front. Installer availability. The good local integrators booked out, so businesses took whoever was free. No leverage. A buyer with a disconnection date eight weeks away is not negotiating; they are accepting. The pricing and the contract term both reflected that.
None of those failures were technical. Cloud phone systems worked fine in 2021. They were failures of timing, and timing is the one part of this that is entirely within your control.
The Things That Quietly Break
This is the section people skip and later wish they had not. When a legacy voice service is disconnected, the phones are the obvious thing that stops. The problem is everything else that was quietly sharing that line, often installed by a different contractor years ago, and not documented anywhere.
| What is attached | What happens | What to do about it |
|---|---|---|
| Fax machine | Analogue fax is unreliable over IP voice paths and often simply fails | Move to an email-to-fax service, or confirm your provider supports fax properly. Medical and legal practices should test with their actual counterparties, not a test page |
| EFTPOS terminal on a dial-up backup | Falls back to nothing; card payments fail during an internet outage | Move the terminal to a mobile or IP-connected model. Ask your bank — most have already retired dial-up |
| Alarm panel / monitored security | Panel may keep reporting locally but stop reaching the monitoring centre — silently | Contact the monitoring provider before the cutover. Most now use IP or 4G dialler modules. Ask for a signal test after the change, in writing |
| Lift emergency phone | Stops working. This is a compliance and a safety problem, not an inconvenience | This is the lift contractor's job, and it needs a booking. Start it early; it is frequently the longest lead time in the whole project |
| Fire panel dialler | May fail to transmit alarms to the monitoring service | Fire services contractor, same as the lift. Do not assume the phone installer will handle it |
| Door intercom / gate phone | Analogue intercoms wired to a legacy line stop | Replace with an IP or GSM intercom, or terminate it on an analogue adapter that your new service supports |
| Back-to-base medical alert | Silently stops reaching the response centre | Contact the alert provider first. In an aged care or disability setting this is the single highest-risk item on the list |
The practical instruction is short: walk the building and write down every device with a phone cable in it. Not the phones — everything else. Then make one call per item, to the contractor responsible for that item, before you set a cutover date. That single afternoon of work is what separates a boring migration from an expensive one.
A related deadline worth checking at the same time
If your premises is still on copper, you may also be facing a separate nbn-driven change on a different timetable. It makes sense to look at both together rather than doing two disruptive projects a year apart — nbn forced fibre upgrades and copper disconnection covers that side, and the 3G shutdown aftermath is the same lesson applied to mobile-connected equipment.
If You Are on Calling for Office 365
This group has the nearest reported deadline and the most specific problem, so it deserves its own section.
Telstra Calling for Office 365 provided the calling layer underneath Microsoft Teams: Teams was the interface, Telstra was the carrier that connected those calls to the outside world. Reported dates put stop-sell at 30 August 2026 and full withdrawal at 30 November 2026.
The critical point, and the one that causes unnecessary panic: Microsoft Teams is not going anywhere. Your Teams tenancy, your channels, your internal calls and meetings are unaffected. What disappears is the external calling path. If you do nothing, Teams keeps working for everything except making and receiving calls to actual phone numbers — which is, unfortunately, the part your customers use.
Option 1: another Direct Routing provider
Keep Teams as the interface and put a different carrier underneath it via Direct Routing. Least disruptive to how your staff work — the app on their screen does not change. You will need a provider that supports it properly; Teams Phone and Direct Routing in Australia covers what to look for.
Option 2: a full cloud phone system
Move calling to a proper cloud phone platform and use it alongside Teams. You gain the things Teams calling has never done well — queues, IVR, call recording, reporting, AI handling — at the cost of a second app for voice.
Option 3: Microsoft's own calling plans
Buy calling directly from Microsoft. Simple to reason about, and worth pricing. Compare it honestly on total cost per user and on what you get beyond dial tone — feature depth and Australian support are usually where the comparison turns.
What to do this month
Count your calling-enabled users, list your numbers, and confirm your reported end date in writing. Those three facts are what every quote will ask for, and gathering them takes an hour.
What Replaces It
There are three honest answers, and which one is right depends far more on whether you already own a phone system than on anything else.
| Replacement | Best when | Watch out for |
|---|---|---|
| Hosted cloud phone system — the platform, apps, handsets and features all provided as a service | You were on DOT or TCO365, or your on-premise PBX is old enough that replacing it is overdue anyway. This is the right answer for most small and medium businesses | Check that call recording, queues, IVR and reporting are included rather than paid add-ons. Compare per-user totals, not headline rates |
| SIP trunks to your existing PBX — replace only the lines | You were on Business SIP, the PBX is genuinely modern, and you have someone who can administer it | You are extending the life of hardware that will still need replacing later. Confirm your PBX is supported and patched. Ask who answers at 6pm when a trunk drops |
| Teams Direct Routing — keep Teams, change the carrier underneath | You were on TCO365 and Teams is genuinely how your people work | Teams calling is thinner than a real phone platform on queues, IVR and reporting. Fine for a team of knowledge workers; usually not enough for a reception desk or a support line |
If you are starting from scratch on the comparison, hosted PBX versus on-premise is the architectural version of this decision and the Australian provider comparison is the shortlist version. For budgeting, what a business phone system actually costs in Australia has the per-seat arithmetic.
The question that separates good options from bad ones
Ask every provider you talk to: “when your platform reaches end of life, what happens to me?” You are having this conversation precisely because a previous answer to that question was unsatisfying. A provider that owns and operates its own network can tell you directly. A provider reselling somebody else's platform is answering on behalf of a company you have no contract with — which is the situation you are currently trying to leave. Who actually owns the network your calls run on is the longer version of that argument.
Porting: The Part That Sets Your Timeline
Everything else in a phone migration can be compressed. Porting cannot, and it is the reason migration projects take as long as they do.
Number portability in Australia is a regulated process. Your provider must support it and cannot refuse a valid request — your numbers are yours, not the carrier's. But regulated does not mean instant, and it does not mean nothing can go wrong.
| Port type | What it is | Typical timeframe |
|---|---|---|
| Simple (Category A) | A single standalone number with nothing attached | Around 2–10 business days with correct paperwork |
| Complex | Multiple numbers, number ranges, or numbers with services attached — which describes almost every business | Around 5–15 business days, longer if anything needs correcting |
The delays are almost never technical. They are paperwork. A port request is matched against the losing carrier's records, and if the account name, address or account number does not match exactly, it is rejected and you start again.
The four things that reject a port
The trading name instead of the registered entity. If the account is in the name of a company that has since changed name or been restructured, the port will fail on the mismatch. An old service address. The address on the phone account, not your current premises. A missing number. Businesses routinely forget a fax number, a direct line to a back office, or an inherited number that still appears on signage and old invoices. Authority from the wrong person. The port has to be authorised by someone with authority over the account. Get your full number inventory and your exact account details before you request anything — porting a business number to VoIP walks through the mechanics.
One more thing that catches people: do not cancel the old service. Cancelling a service releases the number, and a released number may be gone for good. The port itself closes the old service. If anyone advises you to cancel first to save a month's line rental, that advice is worth less than your main business number.
Working Backwards From Your Date
Take your end-of-service date and count backwards. This is the plan, and it is deliberately unambitious — the goal is a migration nobody outside the business notices.
| When | What you do | Why then |
|---|---|---|
| 6 months out | Confirm your product and end date in writing. Walk the building and inventory every device on a phone line. List every number you own | These three facts drive every quote and every timeline. Gathering them later is what causes the compression |
| 5 months out | Contact the contractors for lift, fire, alarm and any monitored device. Ask what their replacement path is and how long they need | These have the longest lead times and the least flexibility. They are the critical path, not the phones |
| 4 months out | Get two or three quotes. Ask each one the end-of-life question. Check whether your internet connection has the upload headroom for voice | You are negotiating from choice rather than from a deadline. This is where the money is saved |
| 3 months out | Decide. Sign. Submit port requests with verified account details | Porting is the long pole, and a rejected request costs weeks. Submitting early means a rejection is recoverable |
| 2 months out | Build the new system in parallel — menus, queues, after-hours, voicemail. Test it on a spare number. Train staff on the app | Running both in parallel is the whole trick. Nothing has been cut over, so nothing can go wrong publicly |
| 1 month out | Port. Confirm every attached device still reports. Get written signal tests from alarm and fire monitoring | A month of margin means a problem is a problem, not an outage on a deadline |
| After | Check the final bill closes the old service. Update numbers on the website, Google profile, invoices, signage and vehicles | The commonest post-migration mistake is a working phone system that nobody can find the number for |
If your reported date is 30 November 2026 and you are reading this in August, you are at the four-month mark. That is comfortable but not luxurious. If your date is 30 August 2027, you have a year, which means you can do this properly and cheaply. Either way, the first three tasks take an afternoon.
Why Moving Early Costs Less
The financial case for starting now is not about the migration cost, which is roughly the same whenever you do it. It is about everything around it.
You are a buyer, not a hostage
A business with a year of runway can compare three providers, ask hard questions and walk away. A business with six weeks takes what is available. The gap between those two positions shows up in the monthly rate and the contract term.
You cut over on a quiet week
Moving early means choosing your own timing — a quiet Tuesday, not the last week of the financial year because that is when the disconnection lands.
You get the good installer
Regional migration waves book out local capacity. Early movers get the integrator with the reputation; late movers get whoever is free.
You collect the upside sooner
The replacement is better than what you have. Call queues, proper after-hours handling, recording, reporting, and calls that reach the CRM. Every month you wait is a month you pay for a frozen product instead of a current one.
You stop paying for a dead end
A product past stop-sell is usually frozen — you cannot add seats or features. Businesses in this position often discover the constraint at the worst moment, when they are trying to grow.
You get to choose accountability
The single most useful thing to take out of this is a preference for providers who can answer for their own platform. One organisation responsible for the network, the platform and the support is one phone call when something breaks.
The honest summary: nothing about this is urgent today, and that is exactly the trap. The ISDN wind-down gave Australian businesses four years of notice and most of them still ended up rushing. The difference between the businesses that found it easy and the ones that found it expensive was not budget, size or technical sophistication. It was whether they started while the date was still far away.
Go and find out which product you are on. That is the whole task for this week.