## Context
Build breaks on AWS Amplify (and Next.js SSR) after upgrading posthog-js: `FormData is not defined` (v1.106.1+). Pinning to 1.106.0 works.
## Verified resolution
Maintainer pauldambra: posthog-js references the browser `FormData` API, so it crashes when evaluated in a server/SSR context on Node <18. Routes forward: (1) upgrade to Node 18+ (FormData) / Node 20+ (File API), Amplify supports Node 18; (2) don't initialize posthog-js on the server at all, guard with `typeof window !== 'undefined'` or lazy-load it client-only (e.g. Next.js dynamic import with ssr:false); posthog-node is the server-side SDK. Later versions (1.229.2+) work for many reporters.