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Rails Major-Version Upgrade Program Playbook

Upgrade Rails across major versions as a staged program. Audit deprecations, dual-boot against both versions, adopt new defaults deliberately, then cut over with a canary.

Difficulty
Intermediate
Phases
4
Total Duration
17 weeks
Roles
4

Major Rails upgrades change framework defaults, deprecate APIs, and require coordinated gem updates. This program runs the upgrade as a staged, test-guarded migration using a dual-boot setup so the application can run against both the old and new versions until the new one is green.

Phase-by-Phase

Readiness and Deprecation Audit. Run the application with deprecation warnings as errors to surface everything the new version will reject. Build a gem compatibility matrix and a strong test baseline. The audit defines the scope of work concretely instead of by guesswork.

Dual-Boot and Incremental Fixes. Configure the app to boot against both Rails versions selected by an environment variable. Fix deprecations and upgrade incompatible gems on trunk, keeping CI green for the current version while progressively passing under the new one.

Framework Defaults and Config. Adopt the new framework defaults deliberately, one at a time, updating initializers and configuration. Feature flags let risky default changes roll out gradually rather than all at once.

Cutover and Cleanup. Remove the dual-boot scaffolding, deploy with a canary, and watch the four golden signals during stabilization. The program ends when the app runs solely on the new version with no deprecations.

Team and Roles

An architect owns the upgrade strategy and default-adoption order. Backend engineers fix deprecations and gems. QA maintains the test baseline. DevOps manages dual-boot CI and the canary rollout.

Risks and Mitigations

Gem incompatibility is the most common blocker; the compatibility matrix identifies it early and the dual-boot keeps work shippable. Changed framework defaults can alter behavior subtly, so adopt them individually behind flags. Silent regressions are caught by the test baseline. Coordinate so the whole team works against one upgrade branch via trunk-based development.

Success Criteria

Success is zero deprecation warnings, maintained or improved test coverage, steady deployment frequency, and good MTTR through the cutover.

Tooling

Use dual-boot gem configuration, a Git-driven CI matrix testing both versions, feature flags for defaults, and canary deployment. PostgreSQL and Redis remain the data and cache backends.

Vibgrate CLI

See a real scan run

A replay of the actual CLI running against our test repositories — live progress, real findings, a genuine DriftScore. Nothing executes in your browser.

Replay
demo@vibgrate — bash
npx @vibgrate/cli scan
 
╭──────────────────────────────────────────╮
Vibgrate Drift Report
╰──────────────────────────────────────────╯
 
── node-turborepo (node) .
Runtime: >=18.0.0 (6 majors behind)
Frameworks:
Turbo: 1.13.4 → 2.10.12 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
1 current 1 1-behind 3 2+ behind 1 unknown
 
── @repo/admin (node) apps/admin
Frameworks:
TanStack Query: 5.102.5 → 5.102.5 (current)
React: 18.3.1 → 19.2.8 (1 behind)
React DOM: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vite: 5.4.21 → 8.2.2 (3 behind)
Dependencies:
3 current 9 1-behind 3 2+ behind 4 unknown
 
── @repo/api (node) apps/api
Frameworks:
Express: 4.22.2 → 5.2.1 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vitest: 1.6.1 → 4.1.11 (3 behind)
Dependencies:
7 current 5 1-behind 3 2+ behind 4 unknown
 
── @repo/web (node) apps/web
Frameworks:
Next.js: 14.2.35 → 16.3.3 (2 behind)
React: 18.3.1 → 19.2.8 (1 behind)
React DOM: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
2 current 6 1-behind 3 2+ behind 5 unknown
 
── @repo/config (node) packages/config
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
2 current 2 1-behind 5 2+ behind 0 unknown
 
── @repo/database (node) packages/database
Frameworks:
Prisma: 5.22.0 → 7.10.0 (2 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
1 current 0 1-behind 3 2+ behind 1 unknown
 
── @repo/types (node) packages/types
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
0 current 0 1-behind 1 2+ behind 1 unknown
 
── @repo/ui (node) packages/ui
Frameworks:
React: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
React: 18.3.1 → 19.2.8 (1 behind)
Dependencies:
1 current 4 1-behind 1 2+ behind 1 unknown
 
── @repo/utils (node) packages/utils
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vitest: 1.6.1 → 4.1.11 (3 behind)
Dependencies:
0 current 1 1-behind 2 2+ behind 1 unknown
 
Tech Stack
Frontend: React, React DOM
Meta-frameworks: Next.js
Bundlers: tsx, Turbo, Vite
CSS / UI: Autoprefixer, PostCSS, Tailwind CSS
Backend: Express
ORM / Database: Prisma, Prisma Client
Testing: Vitest
Lint & Format: ESLint, ESLint Prettier, ESLint React, Prettier, typescript-eslint
 
Services & Integrations
Auth: JWT 9.0.3
Databases: Prisma 5.22.0
 
TypeScript
v5.3.3 · strict ✔ · MIXED · target: ES2022
 
Build & Deploy
Package Managers: pnpm
Monorepo: npm-workspaces, pnpm-workspaces, turbo
 
Product Purpose Signals
Frameworks: react, nextjs
Evidence: 177
Top Signals:
- [heading] Dashboard (apps/admin/src/pages/Dashboard.tsx)
- [title] Revenue Overview (apps/admin/src/pages/Dashboard.tsx)
- [copy] workspace:* (packages/ui/package.json)
- [copy] ./dist (packages/ui/tsconfig.json)
- [copy] ./src/index.ts (packages/ui/package.json)
- [copy] @repo/config/tsconfig-base.json (packages/ui/tsconfig.json)
- [copy] @repo/ui (packages/ui/package.json)
- [copy] #3b82f6 (apps/admin/src/pages/Dashboard.tsx)
Unknowns:
- No pricing or billing evidence found.
- No integrations/connectors evidence found.
- No route structure evidence found.
 
Security Posture
Lockfile ✖ · .env ✔ · node_modules ✔
 
Platform
Native modules: turbo
 
Code Quality
Files: 36 · Functions: 183 · Avg complexity: 2.62 · Avg length: 21.13 lines
Max nesting: 2 · Circular deps: 0 · Dead code: 0%
God files: apps/admin/src/pages/Products (448 lines)
 
Database Schema
postgresql · 8 models · 1 enum
Models: Address, CartItem, Category, Order, OrderItem (+3 more)
 
Findings (16 errors, 11 warnings)
Node.js runtime ">=18.0.0" reached end-of-life on 2025-04-30 (latest: 24.0.0).
vibgrate/runtime-eol in .
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in .
60% of dependencies are 2+ major versions behind in node-turborepo.
vibgrate/dependency-rot in .
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in .
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/admin
Vite is 3 major versions behind (current: 5.4.21, latest: 8.2.2).
vibgrate/framework-major-lag in apps/admin
vite is 3 major versions behind (spec: ^5.0.12, latest: 8.2.2).
vibgrate/dependency-major-lag in apps/admin
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/api
Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).
vibgrate/framework-major-lag in apps/api
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in apps/api
vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).
vibgrate/dependency-major-lag in apps/api
Next.js is 2 major versions behind (current: 14.2.35, latest: 16.3.3).
vibgrate/framework-major-lag in apps/web
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/web
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in apps/web
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/config
56% of dependencies are 2+ major versions behind in @repo/config.
vibgrate/dependency-rot in packages/config
eslint-plugin-react-hooks is 3 major versions behind (spec: ^4.6.0, latest: 7.1.1).
vibgrate/dependency-major-lag in packages/config
Prisma is 2 major versions behind (current: 5.22.0, latest: 7.10.0).
vibgrate/framework-major-lag in packages/database
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/database
75% of dependencies are 2+ major versions behind in @repo/database.
vibgrate/dependency-rot in packages/database
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/types
100% of dependencies are 2+ major versions behind in @repo/types.
vibgrate/dependency-rot in packages/types
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/ui
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/utils
Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).
vibgrate/framework-major-lag in packages/utils
67% of dependencies are 2+ major versions behind in @repo/utils.
vibgrate/dependency-rot in packages/utils
vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).
vibgrate/dependency-major-lag in packages/utils
 
╭──────────────────────────────────────────╮
Top Priority Actions
╰──────────────────────────────────────────╯
 
1. Upgrade EOL runtime in node-turborepo
End-of-life runtimes no longer receive security patches and block ecosystem upgrades.
./.
>=18.0.0 → 24.0.0 (6 majors behind)
Impact: −10 drift points (runtime & EOL)
 
2. Fix security posture: no lockfile found
Without a lockfile, installs are non-deterministic. Run the install command to generate one and commit it.
./
Missing: package-lock.json, pnpm-lock.yaml, or yarn.lock
 
3. Upgrade Vite 5.4.21 → 8.2.2 in @repo/admin (+2 more)
3 major versions behind. Major framework drift increases breaking change risk and blocks access to security fixes and performance improvements.
./apps/admin
Vite: 5.4.21 → 8.2.2 (3 majors behind)
./apps/api
Vitest: 1.6.1 → 4.1.11 (3 majors behind)
./packages/utils
Vitest: 1.6.1 → 4.1.11 (3 majors behind)
Impact: −5–15 drift points
 
4. Reduce dependency rot in @repo/types (100% severely outdated)
1 of 1 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.
./packages/types
typescript: 5.9.3 → 7.0.2 (2 majors behind)
Impact: −5–10 drift points
 
5. Reduce dependency rot in @repo/database (75% severely outdated)
3 of 4 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.
./packages/database
@prisma/client: 5.22.0 → 7.10.0 (2 majors behind)
prisma: 5.22.0 → 7.10.0 (2 majors behind)
typescript: 5.9.3 → 7.0.2 (2 majors behind)
Impact: −5–10 drift points
 
╭──────────────────────────────────────────╮
Architecture Layers
╰──────────────────────────────────────────╯
 
Archetype: nextjs (80% confidence)
Files classified: 24 (11 unclassified)
Folders classified: 8
apps/admin/src presentation 100% 4 files
apps/admin/src/pages presentation 100% 2 files
apps/api/src/middleware middleware 100% 2 files
apps/api/src/routes routing 100% 2 files
apps/web/src/app presentation 100% 4 files
apps/web/src/app/products presentation 100% 2 files
apps/web/src/app/products/[id] presentation 100% 1 file
packages/ui/src presentation 100% 6 files
Unclassified source (sample): 11
 
presentation 15 files drift ████████████████████ 100 risk high
routing 4 files drift ████████████████████ 100 risk high
middleware 2 files drift ███████▍░░░░░░░░░░░░ 37 risk moderate
config 2 files drift ░░░░░░░░░░░░░░░░░░░░ 0 risk none
shared 1 file drift ████████████████████ 100 risk high
 
╭──────────────────────────────────────────╮
DriftScore Summary
╰──────────────────────────────────────────╯
 
DriftScore: 66/100
Risk Level: HIGH
Projects: 9
Classified: 8 nano · 1 micro · 0 small · 0 standard
Billable: 0.42 · 9 detected → 0.42 billable projects (micro-project pricing)
0.1 micro · 0.32 nano
These fractions add up across repositories, then round down to whole billable projects.
 
Score Breakdown
Runtime: ████████████████████ 100
Frameworks: █████████▏░░░░░░░░░░ 46
Dependencies: ██████▏░░░░░░░░░░░░░ 31
EOL Risk: ████████████████████ 100
 
Scanned at 2026-08-26T09:08:28.481Z · 7.1s · 286 files scanned · 56 workspace files · 27 dirs
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