Cracking Google on iOS: What Growth Teams Need to Know About ICM, ODM2, and tROAS

Why now’s the time to prepare for the next wave of iOS performance.

If you’ve been hesitant to scale Google campaigns on iOS, you’re not alone.

Until now, growth teams faced serious challenges – limited measurement, surface-level optimization, and an overreliance on SKAN. Google hasn’t really been able to compete with Meta when it comes to performance on Apple devices.

That’s changing fast.

Here’s What You Need to Know for Your Next Move

• Google’s iOS stack is evolving. SKAN is on its way out.
  
• ICM + ODM2 = the new foundation for attribution and optimization.
  
• tROAS is coming to iOS, but only if you’re ready on the technical front.
  
• First-party (ODM1) + probabilistic (ODM2) signals are key to better models.
  
• Google’s optimization quality should improve by Q4, so build now to benefit then.
  
• Predictive signals matter more than ever. Partnering with Voyantis makes them actionable.
  

What’s Changing Under the Hood

Google has quietly rolled out a set of updates that change the game for iOS advertisers. Here’s what’s new and why it matters:

• ICM (Integrated Conversion Measurement): Google’s new attribution model, currently in open beta for managed clients. ICM enables probabilistic measurement via MMPs like AppsFlyer, which is a major step forward from SKAN. Broader access is expected soon, but the time to prepare is now.
• ODM2 (On-Device Measurement v2): Privacy-safe, probabilistic event data that’s automatically collected via the latest Firebase SDK. It plays a key role in ICM and, based on what we’re seeing with our partners and customers, is expected to unlock stronger optimization for tCPA and tCPI by the end of Q3.
  
• tROAS on iOS: Google is beginning to support true value-based optimization, but only for advertisers who meet specific technical criteria.
  

Together, these updates finally give advertisers the infrastructure to compete, and compare,  across platforms like Meta, TikTok, and AppLovin.

Why This Moment Matters

This isn’t just another product rollout — it’s a strategic shift.

If you’re optimizing for real business outcomes, Google’s new iOS stack makes it possible to:

• Move beyond SKAN’s limits
  
• Run value-based campaigns, not just count-based ones
  
• Train Google’s models with first-party and predictive signals, not guesswork
  

But only if your infrastructure is ready.

Timing Matters: Why You Should Move Now

Google’s models are improving now, but the real performance uplift is expected by Q4 — making this the moment to get your foundations in place. Advertisers who act now will be ready to scale when optimization quality catches up.

How to Get Ready

Here’s what needs to be in place to take full advantage of Google’s new stack:

✅ Bidding to Firebase — required for ICM and tROAS

✅ First-party sign-in data (ODM1) — like email or phone from login events. Improves modeling quality across UAC surfaces, particularly within YouTube and Search placements. Requires manual SDK integration

✅ Probabilistic event data (ODM2) — automatically included in the latest Firebase SDK

✅ Dual consent collection — increases signal strength across Google-owned channels

✅ ICM beta access — currently available to managed clients, with broader rollout expected soon

A Heads-Up on Learning Time

iOS campaigns now take longer to stabilize — sometimes twice as long as Android. Here’s how to stay ahead:

• Make smaller, less frequent changes
  
• Give campaigns time to learn before optimizing
  
• Aim for 15–20 modeled conversions/day (or 100–200 installs/day if you’re still on SKAN)
  

Be patient — the returns will compound as Google’s models improve.

Unlocking Google on iOS with Signal Engineering

To succeed with Google’s evolving iOS stack, you need more than events — you need signals that predict value.

Voyantis makes that possible. We help growth teams generate and pass high-quality predictive signals through Firebase — enabling smarter optimization and more strategic bidding, even before Google’s newest models are fully rolled out.

We’re working with teams across industries to make sure their infrastructure is future-ready — and that they’re not just watching this shift unfold, but leading it.

Let’s Talk

Want to assess your Google iOS readiness?
We’ll help you evaluate where you stand — and what it’ll take to activate tROAS in time for Q4.

→ Start the conversation