Interview with Soren Valtrex: how to migrate legacy code without panic
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Soren Valtrex is the founder of Pheryix and a legacy PHP migration specialist for 9 years. In this interview, he talks about how to safely upgrade old projects.
Q&A
- How to start migrating from PHP 7.4 to 8.3?
Start with a code analysis with Rector + PHPStan. They will show 90% of the problems automatically.
- What are the most common mistakes during migration?
Ignoring types, ignoring breaking changes in functions, missing tests.
- How to avoid downtime?
Use blue-green deployment or feature flags for a gradual switch.
- Do you need Composer from the start?
Yes - it simplifies dependency management and PSR-4 autoloading.

Actionable tips
- Run rector --dry-run on a copy of the project.
- Add PHPStan level 5 and fix all errors.
- Test on a staging environment with real data.
Ready to migrate your project without panic? Get started with the Free Pack or Nexus Course now.