Developer insights, policy updates, and practical guides — curated by the KappS team.
Google Play's Photo and Video Permissions policy has been enforced since May 2025 - eight questions on the picker, declarations and partial access.
Withholding tax is deducted from Google Play earnings in Brazil, Egypt, India, Kenya, Kuwait, Myanmar, Sri Lanka, Taiwan and Tanzania. A step-by-step guide to each rate, the W-8BEN form versus W-9, tax treaty relief, and how to verify your payments profile before a payout cycle.
Google's July 15, 2026 policy refresh confirmed that the User Data policy now covers third-party AI integrations explicitly, and that developers remain responsible for limited use, disclosure and consent. Eight questions cover what counts as an AI integration, what limited use requires, what must be disclosed, and how to audit your AI stack before enforcement does.
Google's white-label best-practices guide now states its preference outright: decentralized accounts beat one central account. The step-by-step workflow for a compliant app matrix: account structure, unique store listings, repetitive-content rules, and review-time guardrails.
Twelve checks against Google Play's 2026 Ads policy: rating match, deceptive and disruptive ads, the 15-second interstitial rule, Families SDKs and ad ID.
AdMob Mediation lets a single ad unit draw fill from many ad sources, and in 2026 the default setup is hybrid: bidding sources run a real-time auction while waterfall sources catch what the auction leaves. This tutorial walks the five console steps (ad unit, ad sources, ad unit mapping, mediation group, SDK and adapters), explains how group priority decides which group fills a request, and covers the details that decide revenue: the 18.3.0 SDK floor for bidding, the a3p signal that proves a bidder is integrated, eCPM floors that override ad unit floors, bidding's exclusion from child-directed traffic, and app-ads.txt.
User choice billing is Google Play's opt-in pilot that lets an eligible app offer its own billing system inside the app, next to Play billing. This guide covers the 2026 rules: the eight pilot markets, the business-account requirement, the fee table that took effect on June 30, 2026 (a flat 10% on auto-renewing subscriptions, 10% to 25% on other digital goods depending on whether the buyer is a new or an existing install), the alternative billing APIs, and the 24-hour transaction reporting rule.
Real-time developer notifications (RTDN) are Google Play's push mechanism for purchase state: Play publishes a base64-encoded event to a Cloud Pub/Sub topic in your own Google Cloud project, and your server receives it by push or pull. This tutorial walks the full setup - creating the topic, the Pub/Sub Publisher grant for google-play-developer-notifications@system.gserviceaccount.com, choosing push versus pull, and sending the Play Console test message - then decodes the DeveloperNotification payload: all subscription notification types, the one-time product events, and the voided purchase notification with productType and refundType. It closes with the server-side rules that keep the pipeline correct: always call the Google Play Developer API for complete status, deduplicate on messageId, acknowledge and process idempotently, and never poll to compensate.
Apple's age rating questionnaire in App Store Connect now produces 4+, 9+, 13+, 16+ and 18+ ratings, with region-specific values for Australia, Brazil and Korea, and an Unrated category that cannot be published on the App Store. Here is what each tier's descriptors mean, which in-app controls you must declare, how Made for Kids and overrides work, and how to answer a region-specific rating notice from App Review.
Google Play began sharing chargeback costs with developers for orders placed after August 3, 2026, so a disputed sale now returns the purchase price less Play's service fee to the buyer and adds the financial institution's chargeback fees to your bill, while Google continues to cover its own service fee. This guide walks the whole money path: how to tell a plain refund from a chargeback in Play Console (the Refunded status variants 'This refund was paid by Google' and 'This refund was a chargeback'), how to wire the Voided Purchases API and its hard constraints (30-day maximum lookback, default and maximum maxResults of 1000, continuation tokens, type=1 for subscriptions plus the switch to orderId, includeQuantityBasedPartialRefund and the missing voidedQuantity that signals a fully refunded multi-quantity purchase), why that API is the only order source that includes processor chargebacks and why it returns revoked orders only, how to answer a PendingRefundReviewNotification within 24 hours through the Review Refund API and why Play records only the first call, how to test the chargeback flow, what a negative balance left standing for 48 hours triggers on your payout bank account, and the user-facing 48-hour refund window that decides whether a dispute ever reaches a bank.
Google Play retires each major version of the Play Billing Library on a fixed two-year cycle, and version 7's new-app-and-update deadline of August 31, 2026 has already passed: new apps and updates must now use Billing Library version 8 or later, with an extension to November 1, 2026 available from the warning on the Play Console Policy status page. This tutorial walks the whole migration: how to find the version an APK actually ships (build.gradle, the BILLING permission, and the com.google.android.play.billingclient.version manifest attribute that manifest merging can strip), how the deprecation table is published two years ahead, the renames that break the compile (setOldSkuPurchaseToken to setOldPurchaseToken, setReplaceProrationMode and setReplaceSkusProrationMode to setSubscriptionReplacementMode), the signature change in ProductDetailsResponseListener.onProductDetailsResponse that now returns unfetched products with product-level status codes, the removal of querySkuDetailsAsync, queryPurchaseHistoryAsync and the parameterless enablePendingPurchases(), what version 9.0.0 and 9.1.0 change (targetSdkVersion 35, BILLING_UNAVAILABLE for a blocked Play Store, a nullable getLinkUri), and what to test before a billing build ships.
Apple's standard App Store commission is 30% of every price an end user pays — Section 3.4(a) of Schedule 2 of the Apple Developer Program License Agreement. Section 3.4(b) of the same schedule reduces it to 15% for developers whose total proceeds stay under $1,000,000 in the prior calendar year, but the test is run across every Associated Developer Account you own or control, app transfers count in the proceeds of every party to the transfer, Apple approves eligible developers within 15 days of the end of each fiscal calendar month, and crossing the threshold mid-year returns you to the standard rate for the rest of that year. This guide covers the enrolment steps, the four ownership tests that define an associated account, the disqualification clause that targets multiple accounts used to benefit improperly, and how to verify the 15% is actually applied.
AdMob pays around the 21st of the month, but only if twelve things were already done. This checklist walks the full payment chain with Google's own thresholds and timelines: the $10 verification threshold and $100 payment threshold, the 45-day identity verification deadline, the PIN mailer that takes about 3 weeks and must be entered within 4 months, the six payment holds nobody checks until money is late, app-ads.txt verification, the certified CMP required in the EEA and UK since 16 January 2024 and in Switzerland since 31 July 2024, and why invalid traffic ends in a disabled account that forfeits participation in both AdMob and AdSense.
Most Google Play developer accounts are not lost to policy enforcement — they are lost to operations: a shared password, an answered phishing email, a change nobody read in the Activity log, a keystore that lived on one laptop, or six months of silence that Google's inactivity policy reads as abandonment. Eight questions answered with Google's own official guidance: 2-Step Verification across every account with Play Console access, why adding users beats sharing a login, what the Activity log records and for how long, how to tell an official enforcement email from a phishing attempt, the correct sequence when an account looks compromised, why the developer account should not be your personal Google Account, where to keep your keystore, and the exact criteria that get dormant accounts closed with no refund.
Core vitals decide whether Google Play quietly reduces your app's visibility or shows shoppers a warning on your listing. This tutorial covers the exact bad behavior thresholds (1.09% user-perceived crash rate, 0.47% ANR rate), where to read your numbers in Play Console, how to automate monitoring with email alerts and the Developer Reporting API, the fix order that actually moves the metrics, and the memory, bitmap and DEX thresholds that start affecting visibility in February 2027.
Play Integrity API returns server-side verdicts on app, device and account integrity. Enable it, request and verify tokens, then roll out safely.
Content ratings on Google Play are issued by IARC member authorities, not Google, and in several regions they decide whether minors can even find your app. Eight answers on the questionnaire, the Summary page, target audience declarations, Families rules, ad suitability, rating overrides, appeals, and the real cost of inaccurate answers.
Play App Signing now runs on three keys: your upload key, Google's app signing key, and the quantum-ready pair for Android 17. Here is how to set it up for a new or existing app, register up to three fingerprints with your API providers, upgrade an app signing key, and reset a lost upload key.
Eight roles decide what your team can do in App Store Connect: Account Holder, Admin, Finance, App Manager, Developer, Marketing, Sales, and Customer Support. Here is how to invite users, restrict app access by role, change or revoke access, and transfer the Account Holder role.
Ten checks that catch rejections and crashes before your AAB reaches users: target API level, upload key and Play App Signing, a Data safety form that matches every SDK, a live privacy policy, content rating, listing assets, and the pre-launch report Play generates for free.
Your Play payouts do not travel from the developer account to your bank directly - they run through the payments profile. Here is how to create the right profile, complete tax information, verify a bank account, and keep payouts from being held.
Play's Location Permissions update, announced April 15, 2026, takes effect January 27, 2027: apps targeting Android 17+ must use the location button as the recommended minimum scope for transactional precise location. Here is how to audit, migrate, and declare in Play Console.
Play's SMS and Call Log Permissions policy, announced July 15, 2026, takes effect January 27, 2027: the READ_CALL_LOG exception for account verification via phone call is removed. Here is how to detect that use case, pick an alternative, and update Play Console.
Play's Contacts Permissions policy, announced April 15, 2026, takes effect January 27, 2027: apps targeting Android 17+ that do not need broad contacts access must use the Android Contact Picker. Here is how to decide, migrate, and declare in Play Console.
After the July 15, 2026 announcement, three Play updates took effect on August 26: Age-Restricted Content covers anonymous and random chat, Families Policy forbids targeting children, and Child Safety Standards expand. Here is the Play Console walkthrough.
If your app lets users create an account, Play's User Data policy requires an in-app deletion path plus a working web link in the Data safety / Data deletion questions. Freezing or disabling is not deletion — here is the Play Console walkthrough for 2026.
Play developers must confirm identity and register remaining package names in Play Console by September 30, 2026. About 99% of apps were auto-registered — here is how to check Home, register leftovers, and avoid global removal.
Play Console gives every developer account three access levels — account owner, admins, and users — plus granular account- and app-level permissions. Here is how to invite teammates, assign the right access, and keep your developer account secure in 2026.
The Apple Developer Enterprise Program costs $299 per year and requires 100+ employees, a D-U-N-S number, a legal entity, and a verification interview. Here is the full registration process in 2026.
Google Play now expects reviewers to reach every AI feature in your app, treats “nudify” prompts as high risk, and cuts off monetization for violators. Eight questions every generative AI app developer should answer before the next submission.
Today is the Google Play target API level deadline: new apps and updates must target Android 16 (API 36)+, and existing apps need API 35+ to stay available on new devices. Here is the 8-point checklist to verify your app is compliant — and what to do if it is not.
How to set up ad monetization for your iOS app in 2026 — create an AdMob account, integrate the Google Mobile Ads SDK, add the GADApplicationIdentifier and SKAdNetworkItems keys to Info.plist, present the App Tracking Transparency prompt, and choose the right ad formats, with Apple Search Ads as a complementary channel.
Renewing your Apple Developer Program membership in 2026: auto-renew setup, the 30-day renewal window, what happens when membership expires, and how to bring your apps back online after a lapse - with the exact steps and deadlines from Apple official renewal documentation.
How to get an app live on Google Play in 2026: build your Android App Bundle, move through internal, closed and open testing, apply for production access, and roll out with staged releases - including the exact testing requirements new personal accounts must meet.
Eight questions about the 2026 Google Play changes that affect developers — the 60-day subscription recovery window, the new in-app subscription management API, delayed charging, Gemini-powered Play Console tools, AI localization, and the compliance deadlines you cannot miss.
What US-based Google Play developers need to know about tax in 2026 — the W-9 requirement in your payments profile, SSN vs EIN rules, exact-name TIN matching, and when Google files a 1099-K (0,000 gross sales and 200 transactions), plus the IRS threshold restored by the One Big Beautiful Bill Act.
Google Play enforces the Developer Program Policies at the policy level, not just per submission - the eight violations behind most rejections and removals in 2026: deceptive behavior and misrepresentation, outdated target API levels (August 31 deadline), unregistered apps, READ_CALL_LOG misuse, anonymous chat apps, unrated content, spam and Mobile Unwanted Software, and deceptive ads - with the fix for each.
What to do when Apple terminates your developer account — read the notice, identify the cited agreement section, gather identity and entity documents, and appeal through Apple Developer Support; a 10-step checklist for the appeal.
How to run an app portfolio on the App Store in 2026 — the right account structure under the Developer Program License Agreement, App Store Connect team roles, Bundle ID hygiene, App Review 4.3 compliance, and a TestFlight release pipeline that scales across many apps.
A complete checklist for transferring an iOS app between Apple developer accounts in 2026 — the app transfer criteria, what transfers with the app and what does not, the 60-day acceptance window, and the exact App Store Connect steps for both the transferor and the recipient.
How to register a Google Play developer account in 2026 — the $25 one-time fee, Personal vs Organization account types, D-U-N-S and identity verification, the new Android device check, and the 12-tester / 14-day closed test rule before production access.
Who must complete Google Play's Data safety form, which data types and purposes to disclose, what counts as collection vs sharing (including SDKs, webviews, and ephemeral data), what is exempt, and the exact Play Console steps to fill, submit, and keep the form accurate in 2026.
What actually puts an Apple Developer account at risk in 2026 - the Program License Agreement termination clauses, what happens when your membership expires, mandatory two-factor authentication, associated-account good-standing rules, renewal re-verification, and where to turn if your account is terminated.
Configure in-app purchases and auto-renewable subscriptions in App Store Connect in 2026 — product types, subscription groups, price points, free trials, sandbox testing, and the App Review requirements for monetization that passes review.
A practical pre-submission checklist for iOS developers in 2026 - verify crash-free TestFlight builds, accurate App Privacy labels, export compliance answers, purchasable IAP products, an active demo account, live backend services, and clean metadata so your app passes App Review on the first try.
How to get paid for paid apps on the App Store in 2026 — sign the Paid Apps Agreement, complete your W-9 or W-8BEN tax forms in App Store Connect, add banking information, and understand country-specific requirements and the 45-day payment schedule.
The eight most common App Store rejection reasons in 2026 — crashes and incomplete builds (Guideline 2.1), beta confusion (2.2), metadata mismatches (2.3), privacy label errors, dead demo accounts, and IAP mistakes — with the exact fix for each and how to resubmit.
A complete step-by-step tutorial for submitting your first iOS app to the App Store in 2026 — App Store Connect setup, Xcode archive and upload, TestFlight beta testing, App Privacy labels, export compliance, and what App Review checks before approval.
Compare the three Apple Developer Program tiers in 2026 — Individual ($99), Organization ($99), and Enterprise ($299) — including D-U-N-S requirements, verification steps, and which membership fits indie developers, studios, and large companies.
A complete checklist for transferring Google Play apps or handing over a developer account in 2026 — registration transaction IDs, Play App Signing keys, payments profiles, integrated services, and exactly what transfers with the app and what does not.
A complete step-by-step tutorial for configuring Google Play monetization in 2026 — merchant account setup, Play Billing integration for IAP and subscriptions, AdMob ad units, and the testing workflow that avoids payment holds.
Six major Google Play policy changes in H1 2026 that directly affect your developer account -- account correlation scoring, publishing limits, 180-day appeal windows, AI review pipelines, data safety enforcement, and stricter SDK privacy manifest rules.
A complete 10-step checklist for appealing a Google Play developer account suspension in 2026 — from identifying the suspension reason to submitting a winning appeal, avoiding common pitfalls, and tracking your case through Google's review pipeline.
A comprehensive Q&A covering the most pressing risk control concerns for Google Play developers in 2026 — account correlation, verification triggers, device fingerprinting, payment holds, and how to keep your publishing matrix healthy.
A practical step-by-step tutorial for setting up shell Google Play developer accounts and building a publishing matrix in 2026 — account isolation, verification strategy, and operational best practices.
The US Tax PIN is the single biggest payment blocker for non-US Google Play developers. Here is exactly how the W-8BEN PIN process works, why your first payment gets held, and how to get your PIN in under 4 weeks.
A developer's pre-flight checklist for Google Play submissions in 2026 — metadata audit, technical requirements, privacy compliance, testing gates, and the 3 most overlooked items that get apps rejected.
Walk through every step of submitting your first app to Google Play in 2026 — console setup, store listing, AAB upload, data safety declarations, pricing, and the final publish button.
Six most common Google Play rejection scenarios — metadata violations, functionality failures, deceptive behavior, content policy, excessive permissions, and low quality. Exact fixes for each one.
Subscription pricing psychology, IAP optimization across Google Play and App Store, and how to recover revenue after payment holds. Data-driven monetization guide for 2026 app developers.
Google Play's Q2 2026 enforcement update introduced account risk correlation scoring. A single violation on one account now raises suspension risk across your entire portfolio. Here's the complete strategy for surviving compliance reviews.
Apple replaced the Resolution Center with a three-tier Appeal Board in 2026. AI handles Tier 1 in 24-48 hours, human reviewers handle Tier 2, and a senior panel resolves Tier 3 disputes. Complete guide inside.
Apple and Google both rewrote their app store search algorithms in 2026. Keywords alone won't rank your app anymore — retention, engagement depth, and creative diversity now decide your fate. Here's the complete guide.
Step-by-step guide to converting your Google Play Individual developer account to an Organization account. Document requirements, timing strategy, and how to avoid the #1 rejection reason.
The $25 Individual account vs Organization account decision determines whether your Google Play portfolio survives a compliance review. Here is why upgrading matters in 2026.
Google Play has quietly introduced account-level publishing limits in 2026. Individual accounts hit a wall at ~20 apps, Organization accounts at ~50. Here is what changed and how to scale past it.
Video verification, 90-day cool-offs, Organization vs Individual conversion — the real playbook that gets Google Play accounts reinstated in 2026.
How top publishers manage 20+ accounts across two app stores without getting flagged. Account isolation, verification strategy, metadata management, and 2026 policy changes for multi-account publishing.
Apple App Store review times have doubled in 2026. Here's what changed inside Apple's pipeline and 5 verified fixes that speed up your app reviews.
A comprehensive comparison between Individual and Organization Google Play developer accounts in 2026. Account types, verification requirements, tax implications, and publishing limits explained clearly.
Apple Developer Program renewal in 2026 — what happens when your membership expires, the grace period window, app removal risks, and the real cost of restarting from scratch.
The 2026 AdMob consent checklist: European regulations message, UMP SDK request flow, canRequestAds, test devices, and US states privacy signals.
Google Play review times are longer in 2026. Inside the pipeline changes and what developers can do to speed up their app updates.
Google Play payment holds in 2026 — the five most common triggers and how to fix each one before your revenue gets frozen.
Six compliance items every Google Play developer needs to verify for H2 2026 — privacy declarations, SDK audits, account verification status, and policy update requirements.
A comprehensive Google Play account health checklist for H2 2026. Verify your account status, tax information, payment profile, and publishing limits.
Google Play tax verification requirements for 2026. What non-US developers need to know about W-8BEN forms, US Tax PIN, and payment holds.
Google's Android Developer Verification mandate enforces identity checks starting September 2026. Here's a comprehensive guide to the verification process, common pitfalls, document requirements, and exactly how to avoid last-minute publishing interruptions.
Google Play Store Listing Experiments let you A/B test your app's store metadata in 2026. Here's exactly how to set up experiments, interpret results, and boost conversion rates by 30%+.
A complete walkthrough for iOS in-app purchase holds and payment recovery in 2026. How to handle App Store payment holds and get your revenue flowing again.
A practical guide to app cloning — project structure, asset management, and metadata migration for multi-account publishing workflows.
Common reasons Google Play accounts get suspended after passing verification, and how to recover your account through the appeals process.
A complete walkthrough of Google Play developer account verification in 2026 — document requirements, tax forms, identity checks, and how to avoid common rejection pitfalls.
A complete developer's guide to app cloning, metadata migration, and multi-account publishing across Apple App Store and Google Play. Best practices for 2026.
IAP holds, tax PIN mismatches, payment profile freezes — what every indie dev should know before launching monetized apps in 2026.
Apple Developer Program Individual vs Organization enrollment in 2026: the App Store seller name, the documents Apple verifies, and the D-U-N-S number rule.
Apple's new active user requirements are reshaping the App Store. Here's what indie developers need to know about the June 2026 guideline changes and how to stay compliant before Q3 enforcement begins.
Apple's June 2026 App Store guideline overhaul — how vibe coding triggered the biggest policy change in years and what it means for developers.
Managing developer accounts across both Apple App Store and Google Play in 2026 requires a coordinated strategy. Here's how to align account structures, document management, and compliance across both platforms.
Complete guide to transferring Google Play developer accounts in 2026. Ownership transfer, documentation requirements, and how to avoid the 90-day lockout.
New personal Google Play developer accounts must complete a closed test with at least 12 testers opted in for 14 consecutive days before they can publish to production. This guide covers the Play Console setup, the production-access application form, the review itself, and the pitfalls that keep new accounts stuck in testing.
TestFlight is the channel every iOS build passes through before release. This tutorial walks the 2026 workflow end to end: the required test information, uploading a build and clearing export compliance, up to 100 internal testers who install instantly, up to 10,000 external testers behind a first-build Beta App Review, invitation emails, redemption codes and public links, tester feedback and metrics, and the 90-day expiry clock that decides your upload calendar.
app-ads.txt tells ad platforms which sellers may sell your app's inventory. The 2026 checklist: link a website, publish at the domain root.
Play Console verification rejected? Read the notice, fix the exact file or field at fault, then resubmit with a compliant identity verification resubmission.
Nine checks to run before you submit identity and bank details for AdSense or AdMob payee verification: name, address, documents and wire must all line up.
Three checks guard a Google Play developer account: KYC identity verification, the AdSense/AdMob PIN, and tax info. Here is how the W-8BEN, the TIN and treaty benefits actually work in 2026.
Managed publishing decouples approval from publication: once a change is approved it sits under Changes ready to publish until you click Publish changes. This guide covers what the Publishing overview page holds back — full and staged rollouts, pre-registration, store listing edits, custom store listings, live store listing experiments, app content and category changes, Managed Play settings and tester configuration — and the exceptions that ship anyway, including raising an existing staged rollout to 100%, release notes, device exclusion rules, tester list membership, price changes and unpublishing. It walks the prerequisites and the five permissions that can switch it on, turning managed publishing on and off mid-review, the Changes not yet sent for review queue with Save for later, the review window that runs from a few hours to seven days, why submitting again mid-review pushes your app to the back of the queue, what changes when a previous update was rejected, and why internal test tracks sit outside managed publishing entirely.
Internal testing is the only Play Console track that can open before your app setup is finished, and the only one That puts a build on a tester's phone within minutes. This tutorial walks the internal track end to end: building a reusable tester email list, the 100-tester ceiling, the shareable opt-in link, what paid apps, device exclusion rules and the Data safety exemption mean for internal testers, how version-code statuses like shadowed and superseded decide what a tester actually installs, and internal app sharing, where one link delivers one build to 100 downloads with a 60-day expiry.
AdMob requires address verification before it will pay you: once earnings reach the $10-equivalent verification threshold, Google mails a 6-digit PIN to your payments address by international standard mail, and you have 4 months from the generation date to enter it. This tutorial covers the documented address format for the mailer, the seven documented reasons a PIN never arrives, the replacement-PIN rules (up to 3 additional mailers, one request every 3 weeks, then the PIN troubleshooter), the alternative identity verification path inside AdMob, and how PIN address verification differs from identity verification and from tax information (W-8BEN / W-9).
What Play Console asks for in 2026: identity documents, photo specs, submission path and review timeline, plus fixes for the five most common KYC rejections.
Every action inside Play Console is gated by a permission, and in 2026 those permissions are organised on three axes: the access level of the person (account owner, admin, or user), the scope of the grant (account-wide or a single app), and an optional expiry date. This guide walks the Users and permissions page step by step: adding and inviting a user, choosing account or app permissions, building permission groups, extending or removing access, the 30-day invitation expiry, what Error 403 actually means, and why payments centre, games services and Account Group access are managed somewhere else.
Country targeting decides which Google Play accounts can install your app, and it is based on where the account is registered rather than where the device happens to be. This guide covers the difference between app availability and per-track targeting, the Production Countries/regions tab, unsyncing a test track from production, restricting a staged rollout to specific countries, and how country changes move through review and managed publishing in 2026.
A staged rollout decides which users are eligible for a Play update, and it is the reason a bad build reaches 5% of your install base instead of all of it. This guide covers the full lifecycle in 2026: choosing a percentage, restricting countries, ramping up, halting a rollout, halting a release that already reached 100%, resuming, and recovering with a new version code.
Google Play enforces hard specs on every store listing asset: a 512x512 32-bit icon, a 1024x500 feature graphic, screenshots from 320 to 3840 px, and separate requirements for tablets, Wear OS, Android TV, Automotive, and XR. Here are the exact specs, the content rules that get listings rejected, and the upload workflow.
Play App Signing keeps your app signing key inside Google's key infrastructure while you hold an upload key. Here is how the keys differ, how new and existing apps enroll, which fingerprints your API providers need, how an upload-key reset works when the keystore is gone, and how app signing key upgrades are enforced across Android versions.