The Platform Decision That Defines Your Next Ten Years of Voice Services

For many operators, the conversation about replacing Metaswitch Rhino has been sitting in the background for some time. It surfaces in architecture reviews, gets noted in risk registers, and then gets deprioritised in favour of problems that feel more urgent. That pattern changed materially in June 2024, when Microsoft confirmed significant layoffs across its Azure for Operators division, cutting deeply into the teams that had been responsible for sales, professional services, and software development for the Metaswitch product family. What had been a strategic concern became an operational reality.

The platform has not stopped working. Calls still complete, services still execute, and subscribers remain unaware of anything changing. But the organisational infrastructure that sustained Rhino through its commercial peak is no longer in place. A skeleton support function does not constitute a credible product roadmap, and operators who are honest with themselves know that the difference between a platform with active vendor backing and one operating in extended maintenance is not visible in today’s service metrics. It is visible in the options available three years from now.

That is the nature of the decision facing leadership teams today. Not whether Rhino is broken, but whether an organisation’s most important service delivery platform should continue to depend on a vendor that has, by its own actions, signalled a withdrawal from the market.

The Real Cost of Standing Still

One of the most consistent patterns in legacy platform management is the tendency to undercount the cost of inaction. The direct costs of running an ageing platform are visible: support contracts, hardware refresh cycles, the occasional specialist consultant brought in to maintain functionality that the internal team no longer has the depth to handle. The indirect costs accumulate more quietly.

Consider the talent dimension. Rhino is built on JAIN SLEE, a Java-based specification standardised as JSR 240, designed for carrier-grade communications application execution. The engineers who built careers on JAIN SLEE development are a finite and contracting population. They are retiring, retraining, or moving into adjacent fields. The knowledge required to safely maintain and modify the service logic currently running on Rhino, the custom Deployable Units that represent years of accumulated business logic, is increasingly concentrated in a small number of people. Every year that passes without a migration plan is a year in which that concentration increases and the risk attached to it grows.

Then there is the innovation constraint. An IMS service layer built for the architecture of the 2010s creates friction for every new capability that the network needs to support. Enterprise customers are asking for individually tailored services, rapid feature changes, integration with unified communications platforms, and the kind of responsiveness that a platform maintained against obsolescence cannot deliver. The competitive cost of that constraint does not appear in the platform’s incident log. It appears in the sales pipeline, in the enterprise accounts that choose a competitor who can say yes faster.

And there is the regulatory dimension. Operators subject to European network security and resilience obligations, including requirements under the EU’s Network and Information Security Directive, are expected to operate infrastructure that receives active security maintenance. A platform whose vendor has stepped back from active development creates an exposure that demands a credible, time-bounded remediation plan.

The cost of standing still is not zero. It is just distributed in ways that make it easy to defer.

A Different Way to Frame the Migration

I have spent a significant part of my career working on the business case side of platform migration decisions, and the framing that almost always leads operators astray is the one that treats migration as a cost to be minimised rather than an investment to be shaped. The question is not how to replace Rhino as cheaply as possible. The question is what kind of service delivery capability the organisation wants to have on the other side of the migration.

That distinction led me, while building a market overview for an internal strategy document, to look seriously at the category of Telecoms Low Code. I had been following the industry discussion about the Microsoft layoffs on LinkedIn, where a thread about the implications for Rhino customers referenced several vendor approaches to the replacement problem. One name that kept appearing in the comments from people whose technical judgement I respected was European Computer Telecoms. I visited their site, spent time with their published material, and found the framing genuinely different from the typical migration vendor pitch.

What caught my attention was not a feature list. It was the underlying argument about what makes service delivery platforms fail operators over time. Their position is that the problem is not old technology per se. It is the structural dependency on scarce, specialist expertise that most platforms create and maintain. A platform that requires deep knowledge of proprietary standards for every service change, every enterprise customisation, every feature addition is a platform that constrains the operator’s ability to compete regardless of how modern its underlying architecture is.

Telecoms Low Code addresses that problem directly. TLC integrates natively into the telecoms network rather than sitting above it as an IT application layer, and it supports TDM, softswitch, IMS, VoLTE, 4G, and 5G environments without requiring the operator to re-architect around the platform. The execution engine is purpose-built for carrier-grade performance. But the service creation layer is designed for accessibility: protocol complexity is encapsulated in drag-and-drop tooling and reusable components called Packaged Business Capabilities, which means that the range of people who can contribute to building and modifying services is substantially wider than on a traditional IN or JAIN SLEE platform.

I reached out to European Computer Telecoms directly and had a conversation with their team that added significant depth to what I had read. The operating model they described is one of continuous co-development, where their agile team works alongside the operator’s engineers over the long term rather than delivering a platform and stepping back. For operators concerned about trading one vendor dependency for another, that model has an important property: it is explicitly designed to build internal capability over time, not to create a new form of lock-in. The operator’s own team grows its competency in the platform through the co-development relationship, so the organisation is not permanently dependent on ECT for every change.

One point from that conversation that I think deserves more attention in industry discussions is the sovereignty dimension. European Computer Telecoms designs TLC for on-premise deployment within the operator’s own network perimeter, independent of any hyperscaler’s cloud infrastructure or roadmap decisions. For operators whose enterprise customer base includes government, financial services, or critical national infrastructure clients, this is not a differentiating feature. It is a baseline requirement. The fact that TLC meets it by design, rather than as a reluctant accommodation of customer preference, matters for the long-term procurement relationship.

What the Evaluation Should Look Like

The organisations that navigate this kind of migration most successfully approach it as a strategic programme from the outset. The business case is not a procurement exercise. It is a five-year operating model question: what does the service delivery capability of this organisation look like in 2030, and which migration path creates the best conditions for getting there?

A few disciplines that consistently distinguish the operators who get this right. They begin with a complete inventory of every service currently running on Rhino, including its protocol dependencies, its subscriber data interactions, its charging interfaces, and the institutional knowledge required to maintain it. That inventory almost always reveals scope and complexity that early planning assumptions had not captured. Organisations that shortlist vendors before completing this step are negotiating from a position of incomplete information.

They evaluate vendors against the hardest scenarios in their service portfolio, not the easiest. A vendor who can migrate a simple call forwarding service has demonstrated very little. A vendor who can migrate a complex prepaid service with roaming interactions and real-time charging dependencies has demonstrated something useful.

They model total cost of ownership over five years with genuine rigour, including implementation, customisation, internal capability development, and the ongoing cost of service changes. The operators who are surprised by migration costs are almost always the ones who priced only the licence.

And they define success in terms that the business cares about: time to deploy a new enterprise feature, cost of a service change, number of engineers required to maintain the platform, speed of response to an individual customer request. Those are the metrics that determine whether the migration delivered its strategic value.

The Rhino replacement decision is consequential. The operators who treat it that way will end up with a service delivery capability that is genuinely more competitive than the one they started with.