Software handover is the least negotiated part of most contracts and the part that decides whether a project survives its first year without the people who built it. It is usually scoped as "a knowledge transfer session", which is a meeting, which is not a handover.
What a real software handover contains
Deployment your team has done themselves. Not watched — done. One of your developers pushes a change and takes it live while the studio sits quietly. If that has not happened, it is not known to work; it is believed to work.
A runbook written against your system. Three to five pages: how to run it locally, how to deploy, where the secrets live, what to do when the common things break, who to call for the parts you do not control. Generic framework documentation is not this.
The environment, reproducible. Someone new should clone the repository and be running locally the same day. If it takes a week of undocumented steps, the project has a bus factor of one and the bus has already left.
A tour of the sharp edges. Every system has three or four places where the obvious change is wrong. An hour spent naming them saves a fortnight later, and they are exactly what nobody thinks to write down.
The list of what is unfinished. Honest, written, with the reasoning. Every project ships with compromises; the dangerous ones are those the next team discovers by stepping on them.
The question worth asking at signature
*If we replaced you the week after launch, how long until the next team ships a change?*
Days is a good answer. Weeks means the handover is a formality. "It depends" means nobody has thought about it, and you should ask again later, in writing.
Why studios skip it
Rarely malice; almost always sequencing. Handover happens in the last week, when everyone is tired and the budget is spent, and it is the only deliverable nobody notices missing on the day. It gets noticed six months later, by which time the people who built the system have moved on and the knowledge is genuinely gone.
The fix is not a bigger budget. It is doing the handover early: your developer deploys in week five rather than week eight, and the runbook is written while the decisions are still fresh. It costs the same and it works, which is a rare combination. Early software handover is built into our eight-week schedule — your developer deploys in week five, with us watching.
Earlier in this series: who owns the code you paid for.