01, Context
The situation
The live game back end comprised approximately 130,000 lines of PHP originating on PHP 5.5. The code existed in fragmented and inconsistent versions, some source was missing, and the system had no established PHPUnit test environment.
02, Recovery
The work
I consolidated the code, reconstructed missing source from first-hand product knowledge and created a living technical specification. I introduced PHPUnit tests, database abstraction and dependency injection, and began moving procedural code toward typed, object-oriented PHP 8.3.
03, Conversion
The AI-assisted upgrade
Using AI-assisted engineering, I completed the initial PHP 5.6 to PHP 8.2 conversion in 14 days. The work included replacing thousands of inconsistently written calls to outdated database-access libraries with consistent modern equivalents.
04, Control
Human review and quality control
The conversion was divided into batches small enough for human sense checking. I checked the early batches heavily, spot-checked the remaining batches and applied an automated quality gate using a test suite developed beforehand with AI assistance.
Very few bugs were found during initial testing. A precise defect count is not recorded, so I do not present one.
05, Outcome
The result
The recovered system could be re-released and continues to be modernised toward typed PHP 8.3. The work established a safer basis for further feature development, performance investigation and live-player support.
06, Relevance
What this proves
AI can accelerate a difficult legacy-software investigation and upgrade when it is paired with domain knowledge, controlled batches, tests and accountable human review. The method is designed to recover understanding and reduce change risk, not to replace engineering judgement.