Yes, with well-organised code (components, state management, tests). We set up that structure from the start.
Yes for structured enterprise applications maintained over the long term. For a lighter project, we will suggest a simpler alternative.
Yes, version by version, with tests at each step. We start with an audit to estimate the effort.
Yes, on a one-off assignment (audit, migration, feature) or through regular maintenance.
On a private server, a cloud service or a specialised hosting platform. Classic shared PHP hosting is usually not suitable.
Yes, with tests to check that results stay identical.