Capacitor App Upgrade (router)#

Plan and run a Capacitor app upgrade one hop at a time, using the version-specific skill for each hop.

When to Use#

TRIGGER when:

• User wants to upgrade a Capacitor app and the start or target version is unknown or more than one major apart
• User asks for "the latest Capacitor" (decide stable 8.5.x vs prerelease 9 with them)
• Xcode 27 builds fail on a Capacitor 8.4-or-older app (needs the 8.5 UIScene step)
• npx cap migrate failed midway and the user needs to know where they are

Do not use:

• Plugin library repos -> capacitor-plugin-upgrades
• Cordova/PhoneGap apps -> cordova-to-capacitor
• CocoaPods to SPM only -> cocoapods-to-spm

Live Project Snapshot#

Current Capacitor packages from package.json: !node -e "const fs=require('fs');if(!fs.existsSync('package.json'))process.exit(0);const pkg=JSON.parse(fs.readFileSync('package.json','utf8'));const out=[];for(const section of ['dependencies','devDependencies']){for(const [name,version] of Object.entries(pkg[section]||{})){if(name.startsWith('@capacitor/'))out.push(section+'.'+name+'='+version)}}console.log(out.sort().join('\n'))"

Native and Capacitor config paths: !find . -maxdepth 3 \( -name 'capacitor.config.json' -o -name 'capacitor.config.ts' -o -name 'capacitor.config.js' -o -path './ios' -o -path './android' \)

Version Map (October 2026)#

Capacitor stable is 8.5.x (latest). Capacitor 9 is a prerelease on the next tag (9.0.0-alpha.x): install with @next until 9.0.0 is GA, then @latest. Ask before moving a production app to a prerelease; 8.5 is the safe stopping point and already builds with Xcode 27.

Procedure#

1. Detect. Read @capacitor/core from the snapshot (npm ls @capacitor/core if ranges are ambiguous). For 8.x, also check whether UIScene is adopted: grep -c UIApplicationSceneManifest ios/App/App/Info.plist.
2. Pick the target with the user if not stated: stable (8.5.x) or prerelease (9).
3. Plan hops. One major at a time, never skip. From 8.0-8.4 to 9, insert the 8.5 UIScene hop first. Examples:
   • 6 -> 9: 6->7, 7->8, 8->8.5 (UIScene), 8.5->9
   • 8.2 -> 9: 8.2->8.5 (UIScene), 8.5->9
   • 8.5 without scene manifest -> 9: run capacitor-uiscene-migration first For big apps, write the hops as a TODO list and confirm it with the user.
4. Per hop: clean git tree, load that hop's skill, install the CLI for the target (npm i -D @capacitor/cli@<major> or @next for 9), run npx cap migrate, finish its manual checklist, npx cap sync, then build iOS and Android. Do not start the next hop until both build. Suggest a commit per hop so failures are bisectable.
5. Plugins. After each hop, align official @capacitor/* plugins to the same major and check third-party/@capgo/* plugins' peer ranges (npm view <pkg> peerDependencies).
6. Final verification (below), then offer follow-ups: cocoapods-to-spm (CocoaPods Trunk expected read-only December 2, 2026), Capgo live updates channel per native version.

Verification#

npx cap doctor
npm run build && npx cap sync
cd android && ./gradlew assembleDebug && cd ..
xcodebuild -project ios/App/App.xcodeproj -scheme App -destination 'generic/platform=iOS Simulator' build   # CocoaPods: -workspace ios/App/App.xcworkspace
npx cap run ios
npx cap run android

On device: launch, pause/resume, deep link cold + warm, push registration, one call per native plugin. If the app ships OTA updates (Capgo), a new native version needs a new native build; never send a bundle built for v9 to v8 binaries (see capgo-live-updates).

Error Handling#

• cap migrate stops partway -> finish that hop manually from its skill; do not start the next major.
• Migrate can only be used on Capacitor 7 -> the installed CLI is newer than the project; step down with the older CLI first.
• UIScene migration: project is in a partial state -> capacitor-uiscene-migration handles it.
• iOS build fails after a hop -> check deployment target and Xcode version against the Version Map.
• Android build fails -> check AGP, Gradle wrapper, JDK, and variables.gradle against the hop's skill.
• Third-party plugin blocks a hop -> upgrade it, replace it (check capacitor-plugins for a Capgo equivalent), or pause at the current hop.