What is the difference between a hotfix and a patch why would you use one instead of the other?

Hotfixes are symptoms of an ongoing problem within software development. While hotfixes intend to fix defects for customers quickly, without waiting for the next full release, they also destabilize the production codebase.

Companies that rely too heavily on hotfixes to boost customer satisfaction tend to make the problem worse and lower the quality of their applications over time. One hotfix is followed by another, and then yet another, until the application is patched or duct-taped together.

Creating a hotfix takes rapid planning and efficient organization to prevent a recurring fire drill. Product owners, developers and testers must plan out an approach to manage hotfixes and remove defects without causing additional issues. In all, hotfixes are a risky but perhaps necessary part of software development.

In this guide, we will explain what a hotfix is, its purpose in software testing, the dangers these updates present, keys to testing hotfixes and tips to avoid them in the first place.

What is a hotfix?

A hotfix is a quick correction to address a bug or defect and typically bypasses the normal software development process. Hotfixes are typically applied to high- or severe-priority bugs that require immediate correction, such as a bug that breaks the functionality or security of the software.

Software development teams always generate defects or bugs — it’s the nature of the work; there’s too much to test and not enough time to do it. As bugs or defects get reported, the organization prioritizes them as critical, severe, high, medium or low (or other similar terms). Critical defects require a hotfix in most cases depending on the release schedule.

What’s the difference between hotfixes, patches and bug fixes?

A hotfix and patch each refer to the same rapid remediation of a defect. In some development teams, software patches refer to a service pack or group of multiple hotfixes deployed at the same time. Hotfixes and patches are often referred to interchangeably.

A bug fix is a standard defect fix that’s coded, then tested, run through regression tests and then deployed as part of a planned release. The majority of software development teams work from backlogs of previously entered defects or bugs.

Test automation plays a critical role in regression testing. But test automation is not a golden hammer, and manual testing plays a critical role in a robust regression strategy.

Bugs come from a variety of places, including customers reporting through the support team, QA test execution or developers finding issues while coding. Bugs are typically logged into a tracking system and then prioritized and fixed for each release. Testers assess bug fixes individually, then place them into a regression testing suite that’s executed before the release. Developers also may create unit tests within the code to automatically test their bug fixes.

Hotfixes are bug fixes, but they are done rapidly. Typically, testers don’t evaluate hotfixes as thoroughly as bug fixes due to time and system constraints.

Typical hotfix timeline

Software developers and testers work in a sprint, a planned set of work, to create new features and bug fixes for each release. When a hotfix occurs, the organization compiles the bug details, then developers and testers discuss a plan for a fast code-and-test routine. Other work stops until the hotfix is coded, tested and deployed.

Once the bug is coded, it undergoes unit testing, then the fix gets deployed to the test server(s). The QA professional assigned to the bugfix validates it in the test server. If it passes, it is deployed to a secondary test server, usually called Staging — though is sometimes deployed straight to Production. Depending on the nature of the fix, such as whether it is a major security vulnerability or critical functionality defect, the QA tester typically runs a basic smoke test against all functionality and the bug fix in production, if possible. Testing within a live Production server carries significant risk, which is why hotfix testing is often only done up to the Staging server.

Once the hotfix is deployed and live, the team returns to its sprint or release work.

The cyclical nature of hotfixes and risks of relying on them

Hotfixes interrupt the release flow for both development and testing teams. It’s distracting to constantly shift work tasks and priorities, yet software development organizations get into the habit of continuously releasing hotfixes.

Constant hotfix releases destabilize the Production server — and introduce new bugs that only result in more hotfixes. Once a company is on the hotfix carousel it’s difficult to stop. But, if it doesn’t stop, the organization risks creating a codebase that is layered with hotfix code that is difficult or impossible to support. The regular release cycle is constantly interrupted, code destabilizes and supporting the codebase becomes trickier every day.

The ultimate result is missed release deadlines and an application with poor overall quality. Customers might like quick fixes, until they cause more quick fixes. At that point, the lack of consistency and chaos might cause the customer to no longer trust the application or the business.

Keys to avoiding hotfixes

The surest method of avoiding hotfixes is increasing the software testing scope, breadth and depth. Plan for full regression testing against a Staging server that mirrors the Production server exactly. Additionally, execute tests against all back-end messaging, database, API and other dependent connections.

Test data must represent real production data at least in type and structure. Testing must encompass configuration settings or customizable settings. Test servers must run the same active connections that Production does rather than rely on simulated connection processing or simulated data loading.

Other keys to avoid hotfixes include:

• improve user story or requirements documentation with actual functional details;

• improve design or consider using prototypes before coding;

• create time for unit test development;

• use automated integrated unit tests before each code deployment;

• consider switching to continuous integration and continuous deployment;

• create more in-depth documentation within development and testing.

4 testing tips for hotfixes

In a tester’s career, they will likely test thousands of hotfixes. They’re unavoidable. When everyone on the team is in fire drill mode and chaos reigns, what’s the best way to test a hotfix as thoroughly as possible?

Here are four critical actions every tester must perform before testing a hotfix.

Understand the work at hand. Discuss the details with the developers coding the fix, including the bug itself and the expected result of the fix

Ask questions. Review the expected functionality with the product team. Based on these conversations, determine what you can and can’t test.

Make a checklist of all items to be tested. In this list, include any integrated functionality that is affected by the defect. Checklists are fast to create and easy to follow during testing, ensuring all relevant items are tested. Checklists also provide base documentation for any test cases written post-deployment.

Regression test around the defect. Determine what other functionality might be impacted by the hotfix correction. Test as much of the associated functionality as possible. Once hotfix testing is completed, add the test steps to the regression or smoke test suite for future execution.

Keep in mind that hotfixes are an extreme measure and should not be common practice. To help boost your test coverage and avoid severe defects in the first place, consider a more comprehensive testing strategy that makes use of global crowdtesters who can mimic the real-world use of your product.

Contact Applause today to learn how some of the world’s leading brands rely on crowdtesting to deliver high-quality digital experiences.

A holistic testing strategy incorporates manual, automated, exploratory, user acceptance and non-functional testing to ensure product quality. Learn more about this approach.

I'd like to point to http://semver.org/ for an attempt to define version numbers in sane manner, and the definitions given there actually fit closely to how I use version numbers (or how I wish I used them :))

As for the term definitions, I find patch and hotfix very similar, except "hotfix" is usually not broadcast if done to a service.

Maintenance Release and Service Pack fit fairly closely to the two denominations of version numbers. if you have a version number structure like X.Y.Z, Maintenance Release would be the Z, Service Pack would be the Y. I've really only heard these terms in big, corporate products, though. I'm more acquainted with the minor/mayor version terms.

Of course, every shop has their own use of the terms, and it depends on which type of user you're targeting. For end-users of MMOs, for instance, every update is a "patch" because the user has to "patch their client" to apply it, while for end-users of more common software, you often just have the term "update" and "new version" (new mayor version).