AdMob 25: error callbacks need a migration check
Removed string callbacks can leave an old mediation adapter outside the supported interface.
An ad integration should be tested when a request fails as well as when it succeeds. The AdMob v25 migration makes that particularly relevant because deprecated callback signatures were removed.
Inspect the failure path
Our recommendation is to list the mediation adapters and custom integrations shipped with the candidate build, then identify the failure callback each implements. An app that compiles through its happy path can still have incomplete diagnostics or an incorrectly handled error in a less frequently used integration.
Use a controlled failure to check that the application receives the expected error information and returns the player to a usable state. Preserve the adapter version and test conditions. Do not treat a forced test failure as evidence of a production fill-rate problem.
Tell growth what the test can establish
A migration check can establish that a particular integration handles a particular failure. It does not establish a revenue uplift, auction advantage or better creative performance. Those claims require a different measurement exercise.
For a hybrid game, our suggested release note to the growth team is practical: which ad placements were exercised, which adapters were covered, and which cases remain untested. That is more useful than marking the entire monetisation stack “updated”. Keep the source migration record attached so a later engineer can understand why the test was added.
The governing record is Migrate SDK versions — v24 to v25. This article checks the provider documentation; it does not inspect a studio account or certify a shipped build.
Inspect the evidence
Download the applicability and deadline record. The extraction separates documented facts from our analysis and unknowns.
| Field | Evidence or limit |
|---|---|
| Provider | |
| Effective or release date | 2026-02-17 |
| Applies to | Android Google Mobile Ads SDK integrations moving from v24 to v25 |
| Documented change | The v25 migration guide replaces specified string-based failure callbacks with AdError-based callbacks. |
| Suggested owner | Mediation integration owner |
| Next verification | Exercise a controlled ad-load failure through each affected adapter. |
Further reading in the existing archive: AppLovin Unity Q2 2025 Earnings: Two Diverging Paths; The MMP Migration Checklist to Run Before You Switch. These links provide background; this check does not independently verify their full contents.
