What it costs to modernise a legacy PHP system

These are starting points, invoiced in USD, GBP, EUR or INR. We say “from” because larger or older systems can go beyond the top tier, and a system on PHP 5.6 is about as old as they come. The same figures are on our pricing page.

You won’t find a cost per line of code here, a typical project figure, or a percentage saving. We have no data we could stand behind, and most of what is published elsewhere has no method attached. We also aren’t publishing what our two PHP 5.6 projects cost.

What we can share is their length. The loyalty-card system took two months, and we had built the original ourselves. The cabinet manufacturer’s system took about eight, with a database move and a new front end. That gap is a fair picture of how far the scope can vary.

• Route. Keeping the code and moving the runtime is a smaller job than rebuilding on a framework. A redesign is larger again. See rewrite or upgrade.
• How the code is built. SQL scattered through page templates has to be read one page at a time, where a data layer can be changed in one place.
• The database. Old MySQL brings encoding repairs, zero dates and a migration to validate. See the MySQL checklist.
• Tests. With none, someone has to check each workflow by hand, or write tests first. That time is part of the price.
• Encrypted data. Anything stored with mcrypt needs decrypting and re-encrypting, as the upgrade matrix explains.
• Connections. Each payment gateway, accounting link, or file exchange with a partner has to be tested, and old ones may need replacing.
• Front end. Keeping the screens costs less than replacing them. Replacing them may still be the right call if dealers or customers depend on them daily.
• How long the old system stays live. A parallel run needs both systems kept in step, which adds work and reduces risk.

Whoever does the technical work, these sit with you, and are easy to leave out of a budget:

• Time from the people who know the system, to explain rules and check results.
• Hosting for old and new during the parallel period.
• Any licence changes for software the new system depends on.
• Training, if screens change.

We can’t put an honest figure on this for you, but you can list the items. Your PHP version gets no more security fixes (see the dates by branch). Packages stop supporting it. Hosts drop it. And, as our cabinet-manufacturer client found, it becomes impossible to hire for and holds back every other change you want to make. Those costs are real, but they tend to arrive all at once rather than month by month.

Start with the modernisation service. Tell us what the system does and, if you can, share read-only access to the code and schema. After a free assessment; fixed price quoted after assessment.