Tesla

Burst Core Configurator: a framework migration under production load

The Burst Core Configurator powers vehicle inventory search, model browsing, and ordering across Tesla’s web and mobile platforms. This engagement covered its migration off end-of-life foundations onto a supported, hardened stack — without a functional regression and without downtime for the ordering path.

The problem

The application ran on Slim 3 with PHP 7. Both had reached end of life: Slim 3 was no longer maintained and PHP 7 long-term support had expired. That combination is a compounding liability — unpatched CVEs with no upstream fix path, dependencies that stop publishing compatible releases, and a migration cost that grows every quarter it is deferred. On a revenue-carrying ordering surface, it is not a deferrable problem.

The work

• Framework and runtime migration. Slim 3 → Slim 4 and PHP 7 → PHP 8, taking the application onto supported security and performance baselines rather than a minimum-viable patch.
• Container rebuild. Worked with the platform team to rebuild the Docker image against Slim 4 and PHP 8 requirements, including restoring image-processing extensions the new runtime needed.
• Dependency remediation. Traced and resolved breakage in downstream packages — including the shared foundation library — that only surfaced once the runtime moved.
• Endpoint-level verification. Built Postman collections and automated scripts covering every endpoint in the service, then ran them with QA and the owning engineers as the release gate. Nothing shipped on the assumption that a framework upgrade is behaviour-preserving.

Why Slim 4

Slim 4 adopts PSR-7, PSR-15, and PSR-11 — standard HTTP messages, middleware, and container interfaces. In practice that means middleware and dependency wiring become portable rather than framework-specific, so the next migration is a smaller job than this one was. Paired with PHP 8’s performance improvements, the service came out faster and materially cheaper to maintain.

Outcome

A revenue-carrying application moved off two end-of-life dependencies onto supported, standards-based foundations — verified endpoint by endpoint, with the security exposure closed and the next upgrade path made cheap by design.

This is the kind of work Birchblue takes on: load-bearing legacy systems where the migration has to be provably safe, not merely finished.