diff --git a/.github/workflows/old-arch.yml b/.github/workflows/old-arch.yml
new file mode 100644
index 0000000..d81b14d
--- /dev/null
+++ b/.github/workflows/old-arch.yml
@@ -0,0 +1,162 @@
+name: Old Architecture
+# RNZA-5: prove v9 still builds when New Architecture is off.
+# playground-rn is RN 0.83 — since 0.82, newArchEnabled=false / RCT_NEW_ARCH_ENABLED=0
+# are ignored. Last opt-out line is RN 0.81.
+
+on:
+  pull_request:
+    branches: [master]
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  RN_OLD_ARCH_VERSION: '0.81.6'
+  RN_OLD_ARCH_CLI: '15.1.3'
+
+jobs:
+  compile-android-0-81:
+    name: Compile Android old-arch (RN 0.81)
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+        with:
+          node-version: 20
+
+      - name: Setup Java
+        uses: actions/setup-java@cf277c60eb25467037889841efdb72551f06f6c3 # v4.9.1
+        with:
+          distribution: 'zulu'
+          java-version: '17'
+
+      - name: Pack library
+        run: |
+          set -euo pipefail
+          TARBALL=$(npm pack --silent)
+          echo "TARBALL=$TARBALL" >> "$GITHUB_ENV"
+          echo "Packed $TARBALL"
+
+      - name: Init RN ${{ env.RN_OLD_ARCH_VERSION }} app
+        working-directory: ${{ runner.temp }}
+        env:
+          CI: '1'
+        run: |
+          set -euo pipefail
+          npx --yes "@react-native-community/cli@${RN_OLD_ARCH_CLI}" init RnzaOldArch \
+            --version "$RN_OLD_ARCH_VERSION" \
+            --pm npm \
+            --skip-git-init \
+            --install-pods=false
+          test -d RnzaOldArch
+
+      - name: Install packed library
+        working-directory: ${{ runner.temp }}/RnzaOldArch
+        run: |
+          set -euo pipefail
+          npm install "${GITHUB_WORKSPACE}/${TARBALL}"
+
+      - name: Disable New Architecture
+        working-directory: ${{ runner.temp }}/RnzaOldArch/android
+        run: |
+          set -euo pipefail
+          grep -q '^newArchEnabled=' gradle.properties
+          sed -i 's/^newArchEnabled=.*/newArchEnabled=false/' gradle.properties
+          grep '^newArchEnabled=false$' gradle.properties
+
+      - name: Assemble release
+        working-directory: ${{ runner.temp }}/RnzaOldArch/android
+        run: ./gradlew :app:assembleRelease --no-configuration-cache
+
+      - name: Assert New Architecture is off
+        working-directory: ${{ runner.temp }}/RnzaOldArch/android
+        run: |
+          set -euo pipefail
+          app_bc=$(find app/build/generated -name BuildConfig.java | head -1)
+          test -n "$app_bc"
+          echo "App BuildConfig: $app_bc"
+          grep -n 'IS_NEW_ARCHITECTURE_ENABLED' "$app_bc"
+          grep -E 'IS_NEW_ARCHITECTURE_ENABLED = (false|Boolean\.parseBoolean\("false"\))' "$app_bc"
+          echo "Library BuildConfig:"
+          lib_hit=$(find . "${GITHUB_WORKSPACE}/android" -name BuildConfig.java 2>/dev/null \
+            | xargs grep -l 'package com.rnziparchive;' 2>/dev/null || true)
+          echo "$lib_hit"
+          if [ -n "$lib_hit" ]; then
+            echo "$lib_hit" | xargs grep -n 'IS_NEW_ARCHITECTURE_ENABLED'
+            echo "$lib_hit" | xargs grep -E 'IS_NEW_ARCHITECTURE_ENABLED = (false|Boolean\.parseBoolean\("false"\))'
+          fi
+
+  compile-ios-0-81:
+    name: Compile iOS old-arch (RN 0.81)
+    runs-on: macos-15
+    timeout-minutes: 45
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+        with:
+          node-version: 20
+
+      - name: Pack library
+        run: |
+          set -euo pipefail
+          TARBALL=$(npm pack --silent)
+          echo "TARBALL=$TARBALL" >> "$GITHUB_ENV"
+          echo "Packed $TARBALL"
+
+      - name: Init RN ${{ env.RN_OLD_ARCH_VERSION }} app
+        working-directory: ${{ runner.temp }}
+        env:
+          CI: '1'
+        run: |
+          set -euo pipefail
+          npx --yes "@react-native-community/cli@${RN_OLD_ARCH_CLI}" init RnzaOldArch \
+            --version "$RN_OLD_ARCH_VERSION" \
+            --pm npm \
+            --skip-git-init \
+            --install-pods=false
+          test -d RnzaOldArch
+
+      - name: Install packed library
+        working-directory: ${{ runner.temp }}/RnzaOldArch
+        run: |
+          set -euo pipefail
+          npm install "${GITHUB_WORKSPACE}/${TARBALL}"
+
+      - name: Install CocoaPods (RCT_NEW_ARCH_ENABLED=0)
+        working-directory: ${{ runner.temp }}/RnzaOldArch/ios
+        run: |
+          set -euo pipefail
+          # RN 0.81 defaults to iOS 15.1; this library requires 15.5 (App Store privacy).
+          sed -i '' "s/platform :ios, min_ios_version_supported/platform :ios, '15.5'/" Podfile
+          grep "platform :ios" Podfile
+          gem install cocoapods -v '>= 1.13'
+          RCT_NEW_ARCH_ENABLED=0 pod install
+
+      - name: Build iOS app
+        working-directory: ${{ runner.temp }}/RnzaOldArch/ios
+        env:
+          RCT_NEW_ARCH_ENABLED: '0'
+        run: |
+          set -euo pipefail
+          WORKSPACE=$(ls -d *.xcworkspace)
+          SCHEME="${WORKSPACE%.xcworkspace}"
+          echo "Using workspace=$WORKSPACE scheme=$SCHEME"
+          xcodebuild \
+            -workspace "$WORKSPACE" \
+            -scheme "$SCHEME" \
+            -configuration Release \
+            -destination 'generic/platform=iOS Simulator' \
+            -derivedDataPath build \
+            CODE_SIGNING_ALLOWED=NO \
+            COMPILER_INDEX_STORE_ENABLE=NO
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91ab2de..101cb5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,15 @@
 
 ## [Unreleased]
 
+### Fixed
+- Android: register as a legacy Native Module when New Architecture is off (`isTurboModule` follows `BuildConfig.IS_NEW_ARCHITECTURE_ENABLED`) so `NativeModules.RNZipArchive` is non-null on old-arch apps (RNZA-5)
+
+### Added
+- CI: RN 0.81.6 old-architecture Android + iOS compile in `.github/workflows/old-arch.yml` (RNZA-5). RN 0.82+ cannot opt out of New Architecture.
+
+### Changed
+- README + MIGRATION: install table by RN version — v7 only for RN < 0.70; v9 on 0.70–0.81 including old architecture; New Architecture only on 0.82+
+
 ## [9.5.0] - 2026-09-04
 
 ### Added
diff --git a/MIGRATION.md b/MIGRATION.md
index 1016651..f8370cb 100644
--- a/MIGRATION.md
+++ b/MIGRATION.md
@@ -19,7 +19,13 @@ The JavaScript API is unchanged from v7 through v9 — no call-site changes. You
 
 Working examples: [playground-expo](./playground-expo/) and [playground-rn](./playground-rn/).
 
-Stay on v7 only for React Native **< 0.70**. On 0.70+, New Architecture is recommended. If the native module fails to load on an old-architecture 0.70+ app, fall back to v7 until Interop is confirmed.
+| Your React Native | What to install |
+|-------------------|-----------------|
+| **< 0.70** | Stay on `^7.0.0` (or upgrade RN first) |
+| **0.70–0.81** | Latest v9. New Architecture recommended; old architecture works. Rebuild native. |
+| **0.82+** | Latest v9. New Architecture only — RN ignores `newArchEnabled=false` / `RCT_NEW_ARCH_ENABLED=0`. |
+
+Old-arch proof is compile + link on RN **0.81.6** (`.github/workflows/old-arch.yml`), not device Maestro. See the [README matrix](./README.md#old-architecture-rn-070081).
 
 ## v9.5
 
@@ -133,7 +139,7 @@ v8.0 migrates `react-native-zip-archive` from Legacy Native Modules to **TurboMo
 
 **JavaScript API is unchanged.** No JavaScript call-site changes are required.
 
-Use v8+/v9 on React Native >= 0.70. Stay on v7 only if you are on React Native **< 0.70**. New Architecture is recommended; old-architecture Interop on 0.70+ is not confirmed — if the native module fails to load, fall back to v7 or enable New Architecture (see Troubleshooting).
+Use v8+/v9 on React Native >= 0.70. Stay on v7 only if you are on React Native **< 0.70**. New Architecture is recommended, not required on 0.70–0.81. Do not add a separate Interop package. RN 0.82+ is New Architecture only — see the [README matrix](./README.md#old-architecture-rn-070081).
 
 ### Migration Steps
 
@@ -145,16 +151,18 @@ npx react-native --version
 
 If you're on React Native < 0.70, stay on v7.x of this library (or upgrade React Native to 0.70+ first).
 
-#### Step 2: New Architecture (recommended)
+#### Step 2: New Architecture (recommended, not required on 0.70–0.81)
+
+This library does **not** require New Architecture on RN 0.70–0.81. On RN 0.82+ you cannot turn it off ([RN 0.82](https://reactnative.dev/blog/2025/10/08/react-native-0.82)).
 
-Follow the [official React Native guide](https://reactnative.dev/docs/new-architecture-intro).
+If you want New Architecture on 0.70–0.81, follow the [official React Native guide](https://reactnative.dev/docs/new-architecture-intro):
 
 **Android**: In `android/gradle.properties`:
 ```properties
 newArchEnabled=true
 ```
 
-**iOS**: Reinstall pods with New Architecture enabled:
+**iOS**:
 ```bash
 cd ios
 RCT_NEW_ARCH_ENABLED=1 pod install
@@ -200,10 +208,10 @@ npm install react-native-zip-archive@^7.0.0
 
 | Issue | Solution |
 |-------|----------|
-| "Native module not found" | Enable New Architecture first. On an old-architecture 0.70+ app, fall back to `^7.0.0` until Interop is confirmed. |
-| Build fails on iOS | Delete `ios/Pods` and `ios/Podfile.lock`, then `pod install` |
+| "Native module not found" | Rebuild the native app (`pod install` + Android rebuild). Stay on `^7.0.0` only for RN **< 0.70**. On 0.70–0.81 with New Architecture off, v9 loads via `NativeModules` after a native rebuild (see [README](./README.md#old-architecture-rn-070081)). If it is still null after rebuild, open an issue with RN version and `newArchEnabled`. |
+| Build fails on iOS | Delete `ios/Pods` and `ios/Podfile.lock`, then `pod install`. This library requires iOS **15.5+**. |
 | Build fails on Android | Run `./gradlew clean` and clear Metro cache |
-| Works on Android but not iOS | Ensure you ran `RCT_NEW_ARCH_ENABLED=1 pod install` |
+| Works on Android but not iOS | Confirm a native rebuild. On RN 0.82+ New Architecture cannot be disabled. On 0.70–0.81, `RCT_NEW_ARCH_ENABLED=1` is optional for this library. |
 | Expo Go shows "Native module not found" | Use Expo Development Build instead |
 
 ### Need Help?
diff --git a/README.md b/README.md
index d4b482c..46a0601 100644
--- a/README.md
+++ b/README.md
@@ -2,13 +2,13 @@
 
 Zip archive utility for React Native.
 
-> Latest **v8+ / v9** targets React Native ≥ 0.70 with TurboModules. **New Architecture is recommended.**
+> **v9** is for React Native ≥ 0.70. New Architecture is recommended. Stay on v7 only for RN **< 0.70**.
 >
-> Use `^7.0.0` only if you are on React Native **< 0.70**:
-> ```bash
-> npm install react-native-zip-archive@^7.0.0
-> ```
-> If the native module fails to load on an old-architecture 0.70+ app, fall back to v7 until Interop Layer support is confirmed.
+> | Your React Native | Install |
+> |-------------------|---------|
+> | **< 0.70** | `npm install react-native-zip-archive@^7.0.0` |
+> | **0.70–0.81** | latest v9 (old architecture works; native rebuild required) |
+> | **0.82+** | latest v9 (New Architecture only — RN ignores the opt-out flags) |
 >
 > **iOS:** Version 7.0.0+ requires a deployment target of iOS 15.5+ to comply with App Store privacy policy.
 
@@ -21,6 +21,31 @@ Zip archive utility for React Native.
 | iOS | >= 15.5 |
 | Android | >= API 23 (Android 6.0) |
 
+## Old architecture (RN 0.70–0.81)
+
+Do not stay on v7 for old architecture on RN 0.70+. Install latest v9 and rebuild native.
+
+| Surface | How v9 loads when New Architecture is off |
+|---------|-------------------------------------------|
+| JS | `TurboModuleRegistry.get('RNZipArchive')`, then `NativeModules.RNZipArchive` |
+| Android | `isTurboModule` follows `BuildConfig.IS_NEW_ARCHITECTURE_ENABLED`; paper specs compile when new arch is off |
+| iOS | `RCT_EXPORT_MODULE` always; `getTurboModule` is `#ifdef RCT_NEW_ARCH_ENABLED` |
+
+| RN | Android `newArchEnabled=false` | iOS `RCT_NEW_ARCH_ENABLED=0` | Evidence |
+|----|--------------------------------|------------------------------|----------|
+| **0.82+** ([playground-rn](./playground-rn/) 0.83.9) | N/A — flag ignored | N/A — flag ignored | [RN 0.82](https://reactnative.dev/blog/2025/10/08/react-native-0.82); zip/unzip Maestro on New Arch (`e2e.yml`) |
+| **0.81.6** (last opt-out) | compile + `IS_NEW_ARCHITECTURE_ENABLED=false` | compile + Legacy Architecture | `.github/workflows/old-arch.yml` (not device Maestro) |
+| **0.73–0.80** | same native paths as 0.81 | same | inferred; not separately built |
+
+Reproduce the 0.81 compile (same as CI):
+
+```bash
+npx @react-native-community/cli@15.1.3 init RnzaOldArch --version 0.81.6 --pm npm --skip-git-init
+cd RnzaOldArch && npm install /path/to/react-native-zip-archive
+# Android: set newArchEnabled=false in android/gradle.properties, then assembleRelease
+# iOS: set platform :ios, '15.5' in the Podfile, then RCT_NEW_ARCH_ENABLED=0 pod install
+```
+
 ## Comparison
 
 | | This library | JSZip in React Native | Nitro (`react-native-nitro-unzip` / `react-native-nitro-archive`) |
diff --git a/__tests__/package-metadata.test.js b/__tests__/package-metadata.test.js
index 50c09e3..a9d658e 100644
--- a/__tests__/package-metadata.test.js
+++ b/__tests__/package-metadata.test.js
@@ -86,10 +86,20 @@ describe('docs claims vs native source (RNZA-7/15/17/19)', () => {
     expect(ios).not.toMatch(/SSZipArchive unzipFileAtPath/);
   });
 
-  test('README does not claim old-arch Interop is proven', () => {
+  test('README documents old-arch v9 load path and playground-rn CI', () => {
     const readme = read('README.md');
-    expect(readme).toMatch(/old-architecture 0\.70\+ app/);
-    expect(readme).not.toMatch(/old architecture is (fully )?supported/i);
+    const migration = read('MIGRATION.md');
+    const pkgJava = read('android/src/main/java/com/rnziparchive/RNZipArchivePackage.java');
+    expect(readme).toMatch(/old-arch\.yml/);
+    expect(readme).toMatch(/newArchEnabled=false/);
+    expect(readme).toMatch(/RCT_NEW_ARCH_ENABLED=0/);
+    expect(readme).toMatch(/Stay on v7 only for RN/);
+    expect(readme).toMatch(/0\.70–0\.81/);
+    expect(readme).toMatch(/0\.82\+/);
+    expect(migration).toMatch(/0\.70–0\.81/);
+    expect(migration).toMatch(/recommended, not required on 0\.70–0\.81/);
+    expect(pkgJava).toMatch(/boolean isTurboModule = BuildConfig\.IS_NEW_ARCHITECTURE_ENABLED/);
+    expect(pkgJava).not.toMatch(/true\s*\/\/ isTurboModule = true/);
   });
 
   test('README records AbortSignal and ZipError usage', () => {
diff --git a/android/src/main/java/com/rnziparchive/RNZipArchivePackage.java b/android/src/main/java/com/rnziparchive/RNZipArchivePackage.java
index 27b785b..dbb0801 100644
--- a/android/src/main/java/com/rnziparchive/RNZipArchivePackage.java
+++ b/android/src/main/java/com/rnziparchive/RNZipArchivePackage.java
@@ -22,6 +22,10 @@ public NativeModule getModule(String name, ReactApplicationContext reactContext)
   public ReactModuleInfoProvider getReactModuleInfoProvider() {
     return () -> {
       Map<String, ReactModuleInfo> map = new HashMap<>();
+      // Follow the host app flag. Hardcoding isTurboModule=true hides this
+      // module from the legacy NativeModule registry when newArchEnabled=false,
+      // so NativeModules.RNZipArchive is null and JS cannot fall back.
+      boolean isTurboModule = BuildConfig.IS_NEW_ARCHITECTURE_ENABLED;
       map.put(RNZipArchiveModule.NAME, new ReactModuleInfo(
         RNZipArchiveModule.NAME,       // name
         RNZipArchiveModule.NAME,       // className
@@ -29,7 +33,7 @@ public ReactModuleInfoProvider getReactModuleInfoProvider() {
         false, // needsEagerInit
         true,  // hasConstants — required for RN 0.70.x compat
         false, // isCXXModule
-        true   // isTurboModule = true
+        isTurboModule
       ));
       return map;
     };
diff --git a/playground-rn/README.md b/playground-rn/README.md
index 3e2c3f8..a6d520a 100644
--- a/playground-rn/README.md
+++ b/playground-rn/README.md
@@ -4,6 +4,12 @@ This is a new [**React Native**](https://reactnative.dev) project, bootstrapped
 
 > **Note**: Make sure you have completed the [Set Up Your Environment](https://reactnative.dev/docs/set-up-your-environment) guide before proceeding.
 
+## Old architecture (RNZA-5)
+
+This app is **RN 0.83.9**. Since React Native 0.82, `newArchEnabled=false` and `RCT_NEW_ARCH_ENABLED=0` are ignored — New Architecture is the only option.
+
+Old-architecture compile proof lives in `.github/workflows/old-arch.yml` against **RN 0.81.6** (last version that can opt out).
+
 ## Step 1: Start Metro
 
 First, you will need to run **Metro**, the JavaScript build tool for React Native.