Software⏱️ 2 min read📅 2026-05-31

How to Fix: PHP Fatal error: Call to undefined function json_decode()

Outdated PHP version causing JSON decoding error. Upgrade to the latest PHP version.

Quick Answer: Upgrade to a newer PHP version, such as PHP 7.x or later.

📋 Table of Contents

  1. 🔍 Why This Happens
  2. 🚀 How to Resolve This Issue
  3. 💡 Conclusion

To resolve the PHP Fatal error: Call to undefined function json_decode(), you need to update your PHP version to a recent one. The current PHP version installed on your server is PHP 5.5.1, which is outdated.

🔍 Why This Happens

  • The json_decode() function was introduced in PHP 5.4, and it's not available in PHP 5.5.1.

🚀 How to Resolve This Issue

Method 1: Update PHP Version

  1. Step 1: Upgrade your PHP version using the package manager for your operating system. For example, on Ubuntu-based systems, you can use `apt-get` to upgrade PHP.

Method 2: Use a PHP Version Manager

  1. Step 1: Install a PHP version manager like `php7.4-fpm` or `php7.4-cli` to manage multiple PHP versions on your system.

💡 Conclusion

By following these steps, you should be able to resolve the PHP Fatal error: Call to undefined function json_decode() and ensure that your PHP version is up-to-date.

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