Software warranty period: bug or change request?
What a software warranty period covers: defects against the agreed scope, not new wishes. The honest test, typical durations, what voids it and sample clauses.
A software warranty period is the time after acceptance during which the supplier fixes, at no cost, defects in what was agreed and delivered. It does not cover new wishes, things that were never specified, or problems caused by someone else’s changes. Most post-launch arguments are about that line. This is for owners who have just received a custom application or are about to sign for one.
Quick answer
- A defect (bug): the software does not do what the agreed scope says, or no longer does what it did at acceptance. Fixed under warranty.
- A change request: anything never specified, however obvious it seems now. You pay, after approving an estimate.
- Configuration and third-party causes (a changed DNS record, an API change on the other side) are neither; usually maintenance work.
- Supplier contracts commonly state warranty periods from 30 days to 12 months.
- The acceptance record decides most disputes, because it fixes what was delivered and when.
The honest test: two questions
For every ticket after launch, ask two things.
1. Was it in the agreed scope? Check the specification, acceptance criteria, approved designs and written answers given during the build. If the behaviour is described there and the software does something else, it is a defect.
2. Did it work at acceptance? If a feature passed acceptance and now behaves differently without anyone touching it, it is a defect. If it never existed, it is a change request, even if everyone “assumed” it would be there.
The grey area is basics nobody writes down, such as not losing data or not showing one customer’s data to another. A professional supplier treats those as defects; put them in the contract anyway.
How long software warranties usually run
There is no single standard. What suppliers publish ranges widely: Canadian studio Paper Leaf calls 30 days the default clause, Polish software house JMR says the warranty normally runs 90 days to 1 year, and G-Group puts the market standard in Poland at 12 months. A longer period costs more, because the supplier carries the risk longer.
In Croatia, if a contract is treated as a contract for work (ugovor o djelu, Art. 590 of the Civil Obligations Act), Articles 604 and 605 say the client should inspect the work and report defects without delay; after inspection and acceptance the contractor is no longer liable for defects an ordinary inspection would have found; a hidden defect must be reported within a month of discovery, and no later than two years after acceptance. The contractual warranty sits on top of that, so read the two together.
Worked example: five tickets after launch
A wholesaler accepted a B2B ordering portal on 1 March, with a six-month warranty. In the first months, five tickets came in:
| Ticket | Classification | Why | Who pays |
|---|---|---|---|
| VAT on invoices is off by one cent on some orders | Defect, under warranty | The spec said VAT per line, rounded to two decimals; acceptance tests used only whole amounts, so the error was hidden | Supplier |
| ”Can we export the order list to Excel?” | Change request | Export was never in the scope | Client, after approving an estimate |
| Order confirmation emails stopped arriving | Configuration | The client’s IT changed the domain’s mail records; the portal was untouched | Client, as maintenance or hourly work |
| Card payments fail since Monday | Third-party cause | The payment provider retired the API version the portal used, announced months ahead | Client, as maintenance; the supplier should have warned |
| Report takes 40 seconds | Change request | Acceptance criteria: under 3 seconds for 20,000 orders. The client now has 200,000 | Client. Had the spec said 200,000, it would be a defect |
The last row shows why numbers in the specification matter: the same symptom is a defect or a change, depending on what was written.
What voids or suspends a warranty
Typical, fair exclusions:
- Someone else changes the code. The warranty then covers only the parts nobody else touched.
- Unpatched or changed hosting that the client manages.
- Changed integrations: the other system changes its API, data format or credentials.
- Use outside the agreed environment, such as a browser or device version the scope excludes.
Why the acceptance record decides disputes
Without a signed acceptance record, both the start of the warranty and “what was accepted” are open to argument. A good record holds the date, the delivered version, the test cases that were run, and the list of known open issues with agreed fix dates. Write into the contract that known issues listed there stay the supplier’s to fix, even if the warranty runs out first.
Sample contract wording
A starting point to adapt with your lawyer:
- Defect: “Any deviation of the delivered software from the agreed specification and acceptance criteria, or from behaviour confirmed at acceptance, not caused by changes made by the Client or third parties. The Supplier removes Defects reported during the warranty period free of charge.”
- Change: “Any new function, modification of agreed behaviour, or requirement not contained in the specification. Changes are carried out on the basis of a written estimate approved by the Client.”
- Third-party cause: “Malfunctions caused by changes in third-party services, hosting or configuration outside the Supplier’s control are not Defects. The Supplier diagnoses them and removes them as a Change or under the maintenance contract.”
Under a fixed price, this definition also keeps the price fair. When comparing quotes, check that each states the warranty length and cover.
Note: this article is informational and is not legal advice. Your rights depend on your contract - have the terms reviewed by a lawyer.
After the warranty ends
Everything around the application keeps changing: libraries, browsers, payment providers. What the maintenance contract and SLA must include, and what maintenance costs, have their own articles. In our monthly maintenance and development partnership the defect, change and third-party categories stay the same after the warranty; only who pays for defects changes. Work outside the warranty is billed at €40-60 per hour excluding VAT, always after an estimate you approve.
Frequently Asked Questions
Is custom software covered under warranty? Usually yes, if the contract says so. The warranty covers defects in the agreed scope for a set period after acceptance, not new features.
What is a typical software warranty period? Supplier contracts commonly state 30 days to 12 months from acceptance. Longer periods are possible, but usually cost more.
Who pays for fixing a bug after handover? During the warranty, the supplier pays for defects against the agreed scope. Change requests, configuration issues and third-party causes are paid by the client.
Does the warranty restart after a fix? Only if the contract says so. A fair middle ground is a fresh period for the repaired function only.
Related Articles
- Software maintenance contract and SLA: what it must include
- Fixed price or time and materials for software?
- Who owns the custom software you paid for?
Arguing with a supplier over “bug or change”?
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