Compatibility testing is a technique to check the functionality of software applications across different web browsers and versions, mobile devices, databases, operating systems, hardware, and networks. This process typically ensures the software applications work correctly across all platforms and environments as intended.

In today’s digital age, the market is flooded with many types of mobile devices and different browsers, each with multiple versions of its own. Currently, 5252 billion people use smartphones, translating to 86.29% of the world’s population. It is predicted to add 1156.2 billion new users by 2028.

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With such a high prevalence of mobile devices, people use different browsers and their diverse versions to access applications and websites. Also, a multitude of devices, including desktops, laptops and tablets, and different operating systems, are used to access these websites and applications. This is because every browser, operating system, and other has unique features and differs in how they render web pages.

Therefore, ensuring that websites and applications are compatible across all platforms that give a seamless user experience is crucial. This can be done with compatibility testing of software applications.

Before the mobile application or website gets released in the market, a compatibility test is performed to ensure its congruence with all hardware, browsers, OS, and others. Compatibility tests ensure that developed software applications (websites and mobile apps) are functional and display correctly across all platforms without glitches.

What is Software Compatibility?

Software compatibility is defined as the application's ability to function accurately with different web browsers, browser versions, hardware, software, mobile devices, and networks without hiccups.

It means that software applications can run on particular operating systems, hardware, and network environments without any conflict or glitches. In simple terms, you can understand software compatibility as interoperability between two and more software applications and different platforms or hardware configurations.

But why does compatibility conflict or glitches arise? The main underlying reasons are differences in hardware configurations, software versions, dependencies, and other factors. For example, a software application developed to function on Windows 7 may not be compatible with Windows 10.

Similarly, newly developed software applications may be incompatible with the old version of the database management system. Thus, addressing this during the Software Development Life Cycle is essential.

Test for software compatibility is important for all software applications to work effectively and efficiently without causing crashes or other issues. This makes compatibility testing a crucial part of the software development process.

What is Compatibility Testing?

Compatibility testing is a type of non-functional testing to verify the function of software applications across different operating systems, browsers, and their versions, devices, hardware, networks, software, and security protocols. You can only perform compatibility tests on a stable website or application.

It happens that developed applications or websites’ functions get impacted when run in different browser versions, resolutions, networks, configurations, etc. This may give rise to errors that can delay the software release process. To overcome such a scenario, you must perform compatibility testing. This will enable the team to ensure compatibility requirements for the software applications are addressed and inbuilt before they get released to the end users.

Through this, you can develop software that works accurately across various configurations. This will give consistent experience and performance of applications and websites across all platforms.

Overall, the compatibility test checks applications and websites' usability, reliability, and performance in different test environments.

Why is Compatibility Testing important?

When a new software application is released in the market, many users access those from various browsers and devices like PCs, smartphones, and tablets. However, if the software application is not tested for compatibility with such browsers, devices, or other platforms, it can make them non-functional.

This can lead users to stop using the application, resulting in a negative user experience and a poor reputation for the organization. Therefore, compatibility tests are needed to ensure their functionality and performance across all platforms are uniform.

Other reasons that highlight the need for compatibility testing are explained below:

• When we perform compatibility tests, it is easy to identify and address any compatibility-related issues that can impact the software’s function across different devices, browsers, etc. With this, we can ensure software applications work as expected across different test environments, and users can access those without any glitches.

• Any compatibility issues in the software application and websites identified at a later stage of development or its post-release can be costly to fix. It is crucial to perform compatibility tests in the development phase of software applications to resolve any challenges, if aroused at the earliest. Thus, this will save time and cost in the long run.

• Compatibility issues impact the organization's reputation, directly related to the poor end-user experience. So, compatibility tests are needed to ensure they work seamlessly across different devices, platforms, and OS. This will improve the organization’s reputation among users, increasing brand loyalty.

Example of Compatibility Testing

Let‘s consider a scenario where an organization has developed a web application that runs on desktops. It is developed to work on Windows OS. Now they want to test its working on different versions of Windows. Here comes the need for compatibility testing, which will be done to ensure the user’s requirements.

During compatibility testing, we will test the application on different versions of Windows, such as Windows 8, Windows 10, and Windows 11. The web application can also be tested on laptops, mobile, and tablets. To ensure that the web application's functionality is consistent and accurate, we can test its performance on each configuration.

In addition, we can test the web application’s compatibility with other popular web browsers, like Chrome, Firefox, Safari, and Edge. This will ensure the application functions correctly when accessed through different web browsers.

Benefits of Compatibility Testing

Testing for compatibility can help organizations meet their application or website requirements. Consequently, when you perform compatibility testing, you get assured of its usability, reliability, and security.

However, to run compatibility tests, you should know their benefits so that they shouldn't be missed in the software development process.

• Improve Software Development Life Cycle (SDLC): Compatibility test finds the defects in the software during the SDLC before it gets released. You can detect bugs or errors in the application and website during its development phase.

• This ensures the timely resolution of the bugs and associated challenges with it. Hence, compatibility tests do not complicate the SDLC, which can happen if the working of the application or website is not aligned across various platforms.

• Detecting bugs early: A compatibility test is significant as it helps to timely detect bugs in the application or website when tested across various platforms. Since the QA encounters related challenges at the early stage of development, a compatibility test gives sufficient time for the team to solve them as a priority. You can efficiently fix the time taking tasks like resolving compatibility issues for various devices, browsers, and OS with compatibility tests.

• Ensure successful software release:Compatibility tests with other tests like unit testing and system testing ensure the application’s usability, scalability, and stability across various platforms. This will help in successful software release without any issues or underlying defects in the application. Hence, with compatibility tests, users’ complaints about the application or website can be avoided.

• Enhance security:Compatibility tests identify any security vulnerabilities related to the developed software application when used in the intended environment. You can address those vulnerabilities early and ensure the security of the applications and websites is not compromised.

Types of Compatibility Testing

There are several types of compatibility tests. Here is a quick breakdown.

Hardware Compatibility Testing

This testing process checks software applications' ability to function on the different hardware configurations. You perform a hardware compatibility test to ensure whether a specific hardware device is compatible with a particular software application, platform, and OS. To perform this test, the test environment needs to be set with different hardware configurations to check each application’s function.

You have to test various hardware components like graphic cards, processors, input and output devices, and storage devices. This is important to ensure they function appropriately and are compatible with the tested application. Its outcome can be used to identify potential issues when software applications and hardware are used together. You can use such information to make changes in the hardware and software to ensure appropriate functioning.

Network Compatibility Testing

This testing process checks the software application’s functioning on different network connections. Its primary purpose is to test the software application and its communication with the network and ensure there are no security, connectivity, and performance issues.

You perform network compatibility tests to ensure the software applications work seamlessly in a particular network environment. For this, you need to connect the application being tested with several networks.

For example, you will check the application’s function on Wi-Fi and data networks like 4G and 5G. You can measure two crucial metrics, speed and bandwidth, which can affect the application’s functioning. If such metrics have the expected outcome, the application is compatible with different network connections.

Operating System Compatibility Testing

This testing process checks the functioning of the software application on the different operating systems and its version. The primary purpose of operating system compatibility testing is to ensure that there is no compatibility issue when an application or website works on a different OS and its version.

For example, if you are testing a mobile application, you can test it on iOS and Android to verify its response on both OS. Or, if you are testing a website, you can run an operating system compatibility test on Windows, macOS, and Linux OS.

The test outcome can fix any issue arising when software is used in different OS and versions. You can use such information to make changes to either the application or component of the OS to ensure they function together and recommend to the end-user which OS works best with applications.

Device Compatibility Testing

This testing process checks the compatibility of the software application on several devices, including laptops, tablets, mobile phones, and desktop systems. The primary purpose of device compatibility testing is to test whether the application or website functions correctly on different hardware devices and configurations without any issues.

In this test, you verify the software application's compatibility with various device components like sensors, cameras, microphones, etc.

Mobile Compatibility Testing

This testing process verifies the function of the software application on various mobile devices. This test refers only to mobile devices to ensure whether software applications or websites can operate correctly on different mobile devices such as smartphones, tablets, and other handheld devices.

You may wonder how to choose the correct mobile devices to perform mobile compatibility tests due to the large number of different devices in the market. Here is the answer. Even though many devices are available in the market, you can go through the market stats to gather information on which device you should perform the test on.

Browser Compatibility Testing

It checks the function of the website and web application on different web browsers like Google Chrome, Mozilla Firefox, Safari, Microsoft Edge, and other popular browsers. Its primary purpose is to ensure that web applications or websites work consistently with similar display and function no matter which browser the user uses.

Browser compatibility testing may also involve testing various browser components like JavaScript, HTML, CSS, and other plugins or extensions. With this, your website and web application can work flawlessly on any browser. You don’t have to ask your end-user to change their browsers, as with an effective browser compatibility test, you will offer a positive experience across all popular browsers, including their legacy and latest versions.

Software Compatibility Testing

This testing process checks the function of the software for its compatibility with other software or third-party tools. You will be able to look at how applications or websites function and respond while communicating with different software. For example, if your application allows users to download PDF files, it should open on Adobe Acrobat. Likewise, if the developed application has an exportable grid view, it should open in Microsoft Excel.

Version Compatibility Testing

This testing process checks the compatibility of the software applications on various versions of web browsers and operating systems. Its main purpose is to ensure that any changes or updates made to software applications do not lead to compatibility issues on a previous version of the software or its components that interact with it.

You have to create test cases on different test scenarios to ensure that the new version of the software can interact with the previous version or its components. Some common areas that need to be tested during the version compatibility test include database, API, user interface, and file format compatibility.

Version compatibility tests are further divided into two parts:

• Backward Compatibility Testing

• This testing process checks the functioning of the new software version with older hardware and software. Here, you test the new applications in their legacy versions. This test is also known as downward compatible.

  This testing process checks the functioning of the new software version with older hardware and software. Here, you test the new applications in their legacy versions. This test is also known as downward compatible.

  For example, the old version of the software application undergoes following backward compatibility testing.

  Window XP → Vista → Win 7 → Win 8 → Win 8.1

• Forward Compatibility Testing

• This testing process ensures the functioning of the software application with future versions. Forward compatibility testing is important to ensure the software can be upgraded to newer versions without any compatibility issues.

  For example, the latest version of the software application undergoes following forward compatibility testing.

  Win 7 → Win 8 → Win 8.1 → Win 10

When to perform Compatibility Testing?

One of the best practices for performing compatibility testing is when the build gets stable enough to test. This is because, at this point, software applications are less likely to undergo any changes in the near future.

OHowever, it is crucial to remember that compatibility tests are ongoing. This means you cannot perform compatibility only when the application or website is stable. You can get compatibility issues at any phase or point of the Software Development Life Cycle; thus, it is crucial to integrate compatibility tests into the overall test strategy.

Here are a few examples of when we should run compatibility tests:

• If there are any changes or updates in the OS used by the application.

• If a software application runs on browsers and requires an update.

• If a software application interacts with any new hardware and needs any related change.

• If a software application uses third-party software and libraries and there is any new update.

Hence, compatibility tests should be performed at different Software Development Life Cycle phases to ensure that applications are compatible with other platforms, software versions, and hardware.

Common Compatibility Testing Defects

The different types of compatibility tests identify different types of defects that may occur due to incompatibility issues. Here are some common defects detected that you should know so that if you encounter any such, you can fix those with effective compatibility tests.

• Changes in UI ( look and feel of the software application)

• Change in font size

• Alignment-related issues

• Dropdown menu issues

• Change in CSS style and color

• Scroll bar-related issues

• Pop-up window issues

• Content or label overlapping

• Video and audio playback issue

• Broken tables or Frames

Checklist for Compatibility Testing

Before performing compatibility tests, you should know about the things that should be checked in applications or websites. This will keep you going with the test without missing any aspects of the application or website and ensure a comprehensive testing process.

Checklists for testing compatibility include:

• Accuracy of HTML and CSS.

• Appropriateness of the SSL certificate for respective browsers.

• End-user forms, fields, and webpage with and without JavaScript.

• Accuracy of DOCTYPE for every webpage.

• Accuracy of the layout across various screen resolutions.

• Font attributes like format, size, and color should be consistent across various platforms.

• Content alignment of applications across various screens.

• Working of images, audio, video, and other multimedia technologies.

• Consistency of navigation within the application.

Compatibility Test Tools

Once you have identified the platform; now your focus should be turned to speeding up the testing process. For this choosing the right tools for compatibility tests are important. Automated testing tools can help speed up the compatibility test process by running tests on multiple devices and browsers.

Here are some commonly used compatibility test tools:

• LambdaTest: It is a cloud-based digital experience testing platform that allows running manual and automated browser testing across 3000 browsers, browser versions, devices, and operating systems. With LambdaTest, you can also perform real-time and real-device testing to check the cross browser compatibility of websites and mobile applications.

• Browsera: It is a web-based tool to test websites for scripting and layout issues. It crawls over your website and creates a report which finds compatibility issues on various browsers. Using Browsera, it is possible to take screenshots of your website in different browsers. Through this, you can easily identify and resolve the issues.

• GhostLab: It is a tool used to perform compatibility tests for your website across all devices simultaneously. You can sync the website across all devices to check its function on different platforms. Both manual and automation testing can be done using GhostLab and give detailed reports on compatibility issues.

Steps to perform Compatibility Testing

Before you perform compatibility testing, you should understand the application's target platforms, including the operating system, hardware configuration, and third-party software versions. For this, you prepare a list of operating systems like Windows and Mac OS; and browsers like Chrome, Firefox, Mozilla, Safari, Edge, and Internet Explorer that are needed for the test.

Along with the above, you need to identify the most used hardware configuration among the end-user. You should also identify the third-party tools on which the software application being tested depends, like plugins, frameworks, or libraries. This will help to ensure that third-party software versions are compatible with the software application.

The compatibility test process can be time-consuming and complicated, involving several platforms and devices. To simplify the test, it can be better understood from the following divided steps:

Design and Configure Test Cases

In this step, the test cases are created to verify the compatibility of the software application with the target platforms. You are required to consider the identified target platforms like different operating systems, browsers, hardware configurations, and third-party software versions. Based on this, you can create test cases that cover all other target platforms.

In creating test cases, different test scenarios should be defined that covers all possible scenarios that end-users may encounter. As a bonus tip, ensure that the test scenario is comprehensive and consider all combinations of target platforms. For example, a test scenario may involve testing the software application on Windows 10 with Chrome version 90. Considering the different test scenarios, created test cases should have clear, concise steps and actual and expected results.

Environment Set Up

When you have test cases, you must set up a test environment to perform compatibility tests. This involves the selection of correct hardware and software configuration, including OS, browsers, and third-party software versions, to ensure website and application compatibility.

You should set up a test environment that simulates the end user's software and hardware configurations to ensure accurate results. For this, you need to install browsers, OS, and third-party software on real devices or virtual devices, like emulators and simulators, to ensure they can be tested individually.

Further, you are required to configure hardware per end-user configurations. This includes RAM, processor, graphic card configurations, and storage.

Test Execution

After setting up the platforms or test environment, it is now time to execute the test cases and scrutinize the result in the selected test environment. You must follow the test case steps precisely and record the test results. While performing test execution, you must ensure the compatibility test is done on each target platform.

In executing the test cases, result analysis should also be done to identify any issue or bug noted during the testing process. All you have to do is record the issue and report it to the development team. However, the documented issue should have a clear description so that it gets fixed at the earliest.

Validation and Retesting

The final step of the compatibility test is validating and retesting. To test the fixed error found during the compatibility test by the development team, the testers are now required to retest the software application.

Retesting is a crucial step as it helps to ensure that the particular error in the applications or websites is resolved without giving rise to any further errors or bugs. You can repeat the testing process until all the test cases are resolved. This validation should be done before moving it to real production.

The steps mentioned above on how to perform a compatibility test can be best executed in a cloud-based platform. Testing for compatibility on a cloud-based environment will eliminate your in-house infrastructure challenges and scalability and reliability issues.

Compatibility Testing on the Cloud

Running compatibility tests on cloud-based platforms lets you test on a wide range of browsers, devices, and operating systems. Such access can be difficult in a local in-house environment. To overcome this, a cloud-based platform can be used to test applications simultaneously across multiple browsers, lowering the efforts and time required for testing.

Continuous testing platforms like LambdaTest enable you to perform manual and automated compatibility testing on 3000+ browsers, mobile devices, and OS. With LambdaTest's platform, you can quickly test your website and mobile application in real user environments by leveraging its real device cloud.

It also offers other features, like parallel testing, automated screenshot testing, and debugging tools, to make identifying and fixing any compatibility issues easy.

Challenges in Compatibility Testing

Specific challenges can arise when performing compatibility tests in either a local or a cloud environment. It is crucial to address those while testing to get reliable test results.

Let us learn a few of those challenges.

• The availability of a sheer number of devices, browsers, and operating systems creates challenges in testing applications and websites on every possible configuration. Such fragmentation makes it difficult to ensure the consistent functioning of the application across all platforms.

• Setting up test environments can be expensive and time-consuming.

• Changing or evolving software technology is another challenge that brings new devices, updated OS, and browser versions. It may happen that applications tested for particular platforms may not function correctly on new software technology.

• Applications and websites are intended to perform in multiple countries. In terms of this, the cross-cultural compatibility issue is a critical challenge. This is because ensuring that the application supports different languages, time zones, and date formats is problematic and can be expensive and time-consuming.

Best Practices for successful Compatibility Testing

Considering the challenges mentioned above in compatibility tests, it is crucial to address those to get reliable test results and high-quality applications and websites. Here are some best practices for performing compatibility tests that should be followed to scrutinize and improve the test process:

Test early and often

Performing compatibility tests early and frequently during the Software Development Life Cycle helps in the early identification and fixation of any related issue. You can be assured that compatibility issues are not left unaddressed and save time associated with fixing them later.

Test on real devices

Testing on real devices is one of the best practices that ensure accurate testing of the application’s function on specific devices and OS. You can identify and address compatibility issues before the software application is released.

Prioritizing critical issues

Prioritize tests for crucial functions and features of the applications and website to ensure that most of their significant aspects are addressed across all platforms. Through this, you will be able to allocate resources more effectively and focus on the important functionality of the application.

Test in different environments

You should perform compatibility tests on different network environments, like slow and unstable networks. This will help you verify the compatibility of applications and websites across all networks.

Collaborate with the development team

Collaboration between the testing and development teams should be practiced during compatibility tests. It will help ensure that compatibility issues are identified and addressed promptly, aligned with development goals and that the application meets the requirements.

Conclusion

Compatibility testing is crucial in this current time, where technology is evolving faster. It is an essential process that ensures software applications can work seamlessly across multiple platforms, devices, and environments. In this tutorial, the process outlined to perform a compatibility test can help you get started.

Following the best practice, you can detect and resolve any compatibility issue early in development. This can save you time and effort. You should prioritize compatibility tests to ensure that software applications and websites meet users' expectations.