Google Sets a 2028 Sunset for Android’s Legacy Mobile Ads SDK

Google will cut technical support for its original Mobile Ads SDK on June 30, 2027, and put ad serving itself at risk a year later, the company said July 6. The move formally classifies the software development kit (SDK, a toolkit for building an app’s ad integrations) that has run in-app advertising on Android for years as legacy code, starting a three-stage countdown toward a June 30, 2028 sunset.

Google paired the deadline with something newer than a migration guide: a dedicated AI agent skill built to execute the code changes itself, the same approach it used weeks earlier for an unrelated SDK-level change. Google’s own developer relations staff have started describing months of work where they barely typed code by hand, and that habit is now baked into how the company expects millions of Android apps to make this jump.

Google Had Been Laying Groundwork Since 2025

The July 6 post, written by Natalia Vargas-Caba of Google’s Mobile Ads Developer Relations team, applies to any developer building for Google AdMob (the company’s mobile app ad network) or Google Ad Manager (its ad-serving platform for larger publishers). Google had quietly published early technical documentation for the rewrite as far back as January 2025, a full year before the SDK’s public beta ever shipped.

The Google Mobile Ads Next-Gen SDK, referred to as GMA Next-Gen SDK, is described in the announcement as a significant rewrite built to improve speed, stability, and the daily experience of building against it. Google is designating the rewrite as Android’s preferred SDK, and everything built on the old codebase now runs against a published clock.

The Three-Stage Countdown to Sunset

The schedule has three named stages, and Google says version 25.x.x of the legacy SDK follows the same pattern the company has used to retire previous major versions. The gap between stages gives teams a fixed runway instead of an open-ended warning.

The sunset stage is the one worth reading twice. Once an app hits it, the legacy SDK gets reported as outdated, and that status blocks further releases through the app store review checks that look for current, supported dependencies. A team that has not migrated by then may find it cannot ship even an unrelated bug fix. Google lays out the technical definitions behind each stage on its published deprecation and sunset schedule.

What the Rewrite Actually Buys Developers

The July 6 notice does not restate performance numbers, but it builds on ones Google published when the SDK shipped in a 27 percent cut in banner ad latency alongside a 17 percent smaller device footprint, in what Google called its biggest mobile ad infrastructure update since the original SDK launched.

Early adopters reported gains beyond those official figures during the beta window, tracked on Google’s own success stories page for the SDK. Revenue is typically measured in eCPM, or effective cost per thousand ad impressions.

• 36 percent eCPM increase for one digital media developer across a three-week test, which nearly doubled average revenue per daily active user.
• 16 percent higher ad fill rate reported by a separate developer after switching over.
• One-third reduction in ANR (Application Not Responding) rates for a mobile game developer, a common trigger for one-star reviews and uninstalls.
• 50 percent cut in slow cold starts reported by that same game developer.

Those gains trace back to a specific technical change: the new SDK requires developers to call its initialization method on a background thread before loading ads, replacing the optional initialization the legacy SDK allowed. Google has said skipping that step risks triggering the ANR errors the case studies above were trying to fix.

Why Is Google Pushing AI Agents to Do the Migration?

Google built a dedicated agent skill, a loadable context file that lets AI coding tools handle the migration’s syntax changes, because its own developer relations team is increasingly writing little code by hand and wants that shortcut available to every Android team racing the deprecation clock.

The skill is named google-mobile-ads-android-migrate-to-next-gen, and Google’s announcement points developers to a page called Migrate with AI tools for details. It is not a one-off experiment. On the third episode of Google’s Ads DevCast podcast, Developer Relations Engineer Matt Landers described a similar migration skill built for moving between AdMob SDK versions, noting explicitly that it was not restricted to any single AI platform and could be loaded into any coding agent. Landers, in that same episode, described going more than six months without writing a line of code by hand, while arguing that knowing what to ask an AI tool to do still requires real domain knowledge, even as the tool increasingly handles the syntax itself.

For developers who would rather work manually, Google still offers a step-by-step guide for leaving the legacy SDK, plus a GitHub repository of sample apps named gma-next-gen-sdk-android-examples.

The Age-Signal Precedent

This is the second time in three months Google has paired a mandatory SDK-level change with AI migration tooling. In May 2026, the company introduced a new signal called TFAT to replace the older TFCD and TFUA settings across the Google Publisher Tag, the GMA SDK, and the IMA (Interactive Media Ads) SDK.

That change also pushed publishers to move away from legacy tags inside SDKs they had already integrated, though Google did not attach a hard cutoff date to it the way it has with this deprecation. Taken together, the two episodes point to a pattern: Google now treats a coding-agent-compatible migration guide as a standard companion to a deprecation announcement, not an occasional extra.

Publisher Revenue Is Already Under Pressure

The timing lands while Google’s own ad business is showing strain. Alphabet’s first-quarter 2026 earnings disclosure showed Google Network revenue, the segment covering AdSense, AdMob, and Ad Manager combined, fell 4 percent year-over-year to $6.97 billion even as Alphabet’s total revenue climbed. AdMob publishers sit inside that same segment, which makes SDK-level speed one of the few levers they control while broader traffic and platform dynamics work against them.

Google’s infrastructure has also had a rough stretch. In mid-January 2026, a two-day technical incident tied to a systemic decline in Ad Exchange match rates cut publisher eCPMs by 50 to 90 percent, an episode unrelated to the Mobile Ads SDK directly but one that showed how much publisher revenue depends on the stability of Google’s ad-serving stack underneath it.

That squeeze shows up elsewhere in mobile advertising too. Liftoff Mobile is pitching investors on a planned IPO built on cross-category ad data, and EA has built its own in-game advertising pitch to brand buyers around 120 million players, both bets on squeezing more value out of the same pool of ad dollars Google is trying to defend with a faster SDK.

What Android Developers Need to Do Before 2027

Apps running the legacy SDK keep serving ads without interruption through the entire supported and deprecated phases, so nothing breaks on July 1, 2026, or even on June 30, 2027. What changes on that second date is who answers the phone: any integration bug found after June 30, 2027, gets solved without direct Google help, through the GMA Next-Gen SDK Discord channel, community forums, or a switch to the new SDK regardless of remaining runway.

Developers are not migrating to unlock new ad inventory. The legacy SDK already supports the full range of formats available in GMA Next-Gen SDK:

• Banner ads
• Interstitial ads
• Rewarded ads
• Rewarded interstitial ads
• Native ads
• App open ads

The decision is about performance, stability, and how long a team keeps a direct line to Google, not about product access. Teams that move earlier simply hold onto that support line longer.

Frequently Asked Questions

Does this deprecation also apply to iOS apps?

The July 6 designation covers Android specifically. Google maintains a separate deprecation timetable for iOS on its developer site, so iOS teams should check that page directly rather than assume identical dates.

What is a Google agent skill?

It is a context file that gets loaded into an AI coding agent, teaching it the specific steps needed for a task like this migration. Google has said the skill built for this SDK change works with any coding agent rather than being locked to one company’s AI platform.

Can developers still reach Google for help after 2027?

Direct technical support for the legacy SDK ends at the deprecated stage on June 30, 2027. Developers who have already moved to GMA Next-Gen SDK can still use Google’s SDK support contact channel and the GMA Next-Gen SDK Discord server, where Google’s team has invited developers to share feedback and troubleshoot directly.

How often is Google updating the Next-Gen SDK?

Google has shipped updates on a monthly cadence since the January 2026 beta, matching the release schedule it separately adopted for the Google Ads API that same month. Google also enabled Next-Gen SDK support for Unity-built apps in June 2026, widening the pool of developers the migration affects.

Will migrating unlock new ad formats?

No. Banner, interstitial, rewarded, rewarded interstitial, native, and app open ads are all available on both SDKs today. The case for moving rests on speed, stability, and keeping access to Google’s support team, not on gaining new inventory.

What should a small development team do right now?

Teams with limited engineering time should prioritize the move before June 30, 2027, since that is the date Google’s direct technical support disappears for anyone still running the legacy SDK. Google’s AI migration skill and its manual guide both exist specifically to make that deadline realistic for teams without dedicated ad-ops engineers.