A Guide to Software Compatibility Testing: What & Why?

The success of even the most advanced website or app depends on thorough compatibility testing. Without compatibility, users won’t be able to access its features.

This article will give you a beginner’s deep-dive into software compatibility testing – what it is, why you need it, its types, and tools for its seamless execution. If you’re asking questions like “What is a compatibility test?”, you’ve come to the right place.

What is Software Testing Compatibility?

Software compatibility testing is a non-functional testing. To simply put, it verifies whether or not an application works across various hardware, operating systems (OS and network configurations). 

At the heart of it, software compatibility testing answers questions on how well software performs on different devices— for example, how a Samsung Galaxy S23 compares to an iPhone 4— and that it will meet user requirements in diverse environments.

With a lot of devices, browsers, and OS versions, this testing is crucial. It addresses the challenges of device and browser fragmentation and ensures the software delivers a consistent user experience. No matter the device or platform, this makes it prerequisite in today’s diverse digital landscape.

Types of Software Compatibility Testing

1.Backward Compatibility Testing:

Ensures the current software version is compatible with earlier ones. It involves scenario testing, data migration checks, and ensuring a smooth user experience during upgrades.

Backward compatibility testing is a practice that verifies whether new changes or updates to a software product remain compatible with its previous versions. It ensures that users can seamlessly transition to the latest release without encountering unexpected issues or disruptions.

During backward compatibility testing, testers assess various aspects of the software, such as data migration, system configurations, functional behavior, user interfaces, performance, security measures, and API integrations. This comprehensive testing process helps guarantee that users can transition seamlessly from older versions to the new one, without sacrificing user satisfaction or encountering data loss.

Check here – How to Avoid Cross Browser Compatibility Issues

2.Forward Compatibility Testing:

Verifies the software’s compatibility with future versions, covering aspects like API compatibility, feature alignment, and performance on upcoming platforms. Both types are crucial for a comprehensive compatibility testing strategy.

Software must be tested for compatibility on various functional and non-functional levels, as explained above. A few compatibility testing types, based on these variant levels, are listed below:

What is Hardware Testing?

In simplest terms, these tests check how the software responds to and works with various hardware configuration commonly used by it’s target user base. The aim is for the site/app to be compatible with as many hardware configurations as possible and realistically required.

What is Network Testing?

How is your app going to work when using 2G internet, as opposed to 5G? Perhaps it needs to suspend certain features/design elements from loading so as to continue functioning. This form of compatibility testing checks that these optimizations work exactly as expected in real-world usage. Its aim is to ensure that the software works with different connectivity conditions without compromising user experience too drastically. 

What is Operating System Testing?

This sub-category of compatibility testing verifies if software functions and appears as it is expected to, when running on different operating systems and their versions. This includes desktop and OS-specific OSes, and different versions of each OS. 

What is Device Testing?

This form of testing verifies if the software works optimally on different devices with their variant manufacturing models, screen sizes, and resolutions. Responsive testing is an important part of device compatibility testing.

What is Mobile Compatibility Testing?

In this case, you’re testing if your software is aligned and fully functioning on different mobile devices, browsers, and OSes. Needless to say, there is quite a bit of overlap with browser, device, hardware, and OS compatibility testing. 

What is Browser Testing?

There are many popular browsers (other than Chrome) that you use base will leverage to access whichever website you are developing. This form of testing ensures that said site works without hassle on all/most of these browsers, as well as the different versions of each of those browsers. 

What is Software Compatibility Testing?

Software compatibility testing is the overarching term for ALL tests run to ensure that certain software is compatible with different, browsers, devices, OSes, hardware, third-party configurations, network conditions, and any other parameters that it will encounter when being used by actual users.

What is Version Testing?

All software in which YOUR software is expected to work will be updated regularly. For example, Chrome will launch updated versions consecutively (and quite frequently these days) for better usability and security, as will every other browser. The same goes for OSes. Your site or app must continue working well with every single version, updated or older. To ensure that it does so, you have to undertake version compatibility testing. 

Importance – Why Should You Perform Software Compatibility Testing?

If you intend that your software will cater to a global, national, or even state-wide user base, you can expect it to be accessed from a bafflingly large variety of browsers and devices. To cater to each of these users, your app/website needs to be compatible with each individual users’ hardware-software setup. 

This can also be ensured via compatibility testing in software testing. You basically run your software through multiple device-browser-OS configurations, and monitor its behavior on each. If bugs show up in particular tech environments, your dev team knows exactly what needs to improve for the software to carry wide user appeal and efficacy. Read More: Cross Browser Testing Guide

When Should You Perform Compatibility Testing?

In modern software development, the answer is “always”. 

Think about it. What app/website would not want to gain the highest possible number of users? Getting hundred, thousands, or millions of users to download, install and use an app or access a website is the definition of “success” for any released software. That is its primary goal. 

You’ll be hard-pressed to find any location in the world where users are so homogenous with their device-browser-OS choices that you can test your software on a few popular devices and be done with it. Even in the US, where Apple users are the majority, you still have to run compatibility tests to ensure that software works as expected on different iPhones, iPads, and MacBooks. Apple’s constant drive to improve its product features means that your software may not comply with the security standards, features, usage patterns, etc. of newer models. 

Naturally, you need to execute compatibility tests to adjust the software for usage across all devices, browsers, and OSes. Therefore, you perform compatibility testing anytime you expect your software to be accessed by more than one kind of user environment. 

Read More: Cross Browser Compatibility Testing

When to Automate Compatibility Testing?

Automation of compatibility testing is key to the achievement of a complete and effective assessment of software in a wide range of environments. 

So what a good test suite for compatibility should include? Here it is:

Browser Compatibility: Makes sure the application works well with different browsers and their versions.

Device Compatibility: It tests performance on various devices such as smartphones, tablets, and desktops with different resolutions and screen sizes.

Hardware Compatibility: It evaluates the compatibility of the app with various hardware configurations such as processors and memory.

OS Compatibility: It checks operations on different operating systems and their versions— Windows, Linux, Android, and iOS.

Network Connectivity: It should be tested under different network conditions from 5G to no network at all.

Geolocation/Localization: It should also be tested from different geographical locations and regions.

Considering how intricate tests can be across these variables, manual testing across them is often impractical because of time and resource constraints, as well as issues of scalability. 

Read More: Cross Browser Compatibility Testing

Automation simplifies the process by making it possible to carry out simultaneous tests in multiple environments. Automating compatibility testing not only quickens the process but also improves its accuracy. 

Testsigma for Automating your Compatibility Testing

Testsigma is such a tool, for it provides robust solutions for this need. With Testsigma, QA teams can:

Automate Testing Across Thousands of Configurations: Test across 3,000+ real browsers and devices from a single portal.

Run Parallel Tests: Get results faster by running multiple tests at once.

Write Browser-Agnostic Tests: Write tests in English with no extra code.

Maintain Scripts Efficiently: This is taken care of by Testsigma’s AI, which manages UI updates and handles regression issue detection automatically.

Conduct Multi-Device Visual Regression Testing: Analyze user journeys and deep dive into specific features with granular controls.

Use Interactive Debugging: This helps in the rapid detection and resolution of issues while the tests are running.
Curious? Check out the full range of Testsigma’s capabilities for automated cross browser testing (without code or setup).

How to Perform Compatibility Testing – Manual and Automated?

Steps to execute manually:

1. Have the list of target devices/operating systems/databases/browsers that need to be supported. Ensure that all selected combinations are available.
2. Select the test cases that need to be executed on all the selected combinations in step 1.
3. Execute the selected test cases on the selected combinations.

Steps to execute via an automated tool:

1. Have the list of target devices/operating systems/databases/browsers that need to be supported. Ensure that all selected combinations are available.
2. Ensure that you can automate the tests to be executed on the devices available in step 1.
3. The test cases that need to be executed for this testing should be automated in the test automation tool of your choice.

Schedule the execution of test cases created in step 3, as and when needed.

Below is a document showing how to perform compatibility testing with Testsigma: Test Plan for Cross Browser Testing

Compatibility Testing Checklists

• Validate your HTML, XHTML, and CSS. No open tags. 
• Validate the SSL certificate and ensure it is compatible with most browser versions
• Validate the site or app’s responsive design, 
• Validate all site/app fonts, design elements, and fields. 
• Verify that all layouts, styles, and design are consistent across user environments.
• Validate that images load and render accurately. 
• Check that all fonts, colors, headers and footers are consistent. 
• Ensure that spacing between text and images appears as expected across versions. 
• Check that that scroll, zoom in/zoom out, mouse hover functions as well as the drop down menus are working properly. 
• Ensure that tables and grids are well-aligned, and that pop-ups (if any) appear as expected.

Check here – Cross Browser Compatibility Testing Checklist

Advantages of Compatibility Testing

• Verifies that an app or site is ready for usage across your entire target user base. 
• Ensures that the app or site works in different user conditions – low network connectivity, different browser-device-OS combinations, etc. 
• Ensure that users can access and utilize the app or site from all authorized/approved locations, be it from different countries, states,, or local areas. 
• Ensures that the app complies with and meets regulatory standards for different areas and cultures. 
• Ensures that the app or site is aligned with different cultural sensitives, customs, and preferences.

Compatibility Testing Test Cases

Before we write compatibility test cases, let’s understand the categories. Each category focuses on different aspects, such as,

• OS testing – checks how the application works on different operating systems. It has two sub-categories,
  • Forward compatibility testing – tests the application’s behavior on the latest OS versions
  • Backward compatibility testing – tests the application’s behavior on older OS versions
• Cross-browser testing – checks how the applications work on different browsers and versions.
• Network testing – evaluates how the application works on various network conditions
• Device testing – shows how the application functions on different device specifications.

Let’s create compatibility test cases for the below web page. 

Below are some of the cross-browser test cases that check the cross-browser compatibility of the application on different browsers,

• Verify that the web pages render correctly on different browsers.
• Check for differences in font rendering, spacing, and layout.
• Test the application at different zoom levels to ensure content remains readable and accessible.
• Test form submissions and validation on different browsers.
• Ensure that form elements, such as text fields, checkboxes, and radio buttons, work properly.
• Test on older browser versions to ensure backward compatibility.
• Verify that scrollbars appear and function correctly.

Read here about the subset of compatibility testing i.e,- Installation Testing.

Common Compatibility Testing Defects

Some bugs/defects you are most likely to come across when running compatibility tests across different devices, browsers, and OSes:

• Changes in font size, button size, and other design elements
• Changes in UI elements such as aesthetics
• Changes in CSS, style, and color (font, design elements, background)
• Anomalies with scrolling and content placement (it is common to see a button cover up part of some text, for example)
• Overlapping content/design elements
• Broken tables and/or frames

Types of Bugs in Software Compatibility Testing

Compatibility bugs refer to the issues that occur on one platform but not on another. For example, a bug that surfaces on Windows but not on Mac or other platforms. Some of the compatibility bugs include,

• Changes in UI appearance (look and feel)
• Modifications in font size
• Change in color and CSS style 
• Alignment-related issues
• Content or label overlapping
• Broken Frames or tables
• Scroll bar-related problems

What is the Most Challenging part of Compatibility Testing?

Undoubtedly, the most challenging part of this testing is actually accessing all the browsers, devices, OSes, network conditions, and other elements required to replicate actual specifics of the production environments within your testing ecosystem. 

Unless you have a massive budget at hand, you cannot buy/maintain/update the thousands of devices you need to run a comprehensive compatibility test suite. Thankfully, with tools like Testsigma at hand, you don’t have to. 

Sign up for Testsigma (for free), and you can access 3000+ browsers and devices without having to buy any of them. Payment for a single plan can facilitate compatibility tests on every user endpoint you can imagine. You can also access in-built features that simplify and accelerate your test cycles, and enable faster time-to-market in order to provide a decided advantage over all your competitors in a dog-eat-dog digital marketplace.

Should Compatibility Testing be Automated?

In light of the above reason, it’s quite safe to say that, “Yes, compatibility testing should be automated as your budget/stakeholder approvals allow”.

Wrap-up Time!

Here you go with a summarization.

Software compatibility testing when done properly, helps to prevent costly issues. Not only does this improve user satisfaction through efficient automation, but a great deal of time can be saved (and esp with compatibility testing tools like Testsigma, it’s often easier).