As of my knowledge cutoff date (September 2021), the latest version of CodeIgniter 4 was 4.1.4. However, there may be newer versions available since then.
CodeIgniter 4 is a PHP web application framework that is designed to be lightweight and fast. It has several new features and improvements over its predecessor, CodeIgniter 3, including:
- Better performance: CodeIgniter 4 has improved performance due to its use of PHP 7 features and new caching strategies while CodeIgniter 3 supports PHP 5.2.4 and later.
- Folder Structure: The folder structure of CodeIgniter 4 has been revamped compared to CodeIgniter 3, with changes to the location and naming of some folders.
- Modular Approach: CodeIgniter 4 has a modular approach, allowing developers to create self-contained modules that can be easily reused across multiple projects. CodeIgniter 3 does not have this feature.
- Namespace Support: CodeIgniter 4 uses namespaces, allowing developers to organize their code more efficiently and prevent naming conflicts. CodeIgniter 3 does not support namespaces.
- Dependency Injection: CodeIgniter 4 includes built-in support for dependency injection, making it easier to manage dependencies and create more modular code. CodeIgniter 3 does not have this feature.
- Query Builder Improvements: CodeIgniter 4 includes improvements to the query builder, such as support for subqueries and better handling of complex queries.
- Improved error handling: CodeIgniter 4 has improved error handling with more detailed error messages and stack traces.
- Compatibility with modern web technologies: CodeIgniter 4 has improved support for modern web technologies like HTML5 and CSS3, making it easier to build modern, responsive web applications.
- RESTful API support: CodeIgniter 4 includes built-in support for building RESTful APIs, making it easier to build web services and mobile apps.
Compared to its predecessor, CodeIgniter 4 has a more modern architecture, better performance, and improved support for modern web technologies. However, upgrading from CodeIgniter 3 to CodeIgniter 4 may require some changes to your code, as some features and APIs have been removed or changed.
