Please refer to the upgrade instructions corresponding to your installation method.

CodeIgniter provides a few functions and variables that are globally defined, and are available to you at any point. These do not require loading any additional libraries or helpers.

CodeIgniter features wrappers around some of the most popular forms of fast and dynamic caching. All but file-based caching require specific server requirements, and a Fatal Exception will be thrown ...

BCC Batch Mode, enabling large email lists to be broken into small BCC batches. Sending email is not only simple, but you can configure it on the fly or set your preferences in the ...

The following page contains example code showing how the database class is used. For complete details please read the individual pages describing each function. Note CodeIgniter doesn’t support dots ( ...

The Database Utility Class contains methods that help you manage your database.

Many functions previously found in the CodeIgniter 3 date_helper have been moved to the Time class in CodeIgniter 4. It is recommended to use the Time class instead. Use Time::now()->getTimestamp() to ...

The HTML Helper file contains functions that assist in working with HTML.

The IncomingRequest class provides an object-oriented representation of an HTTP request from a client, like a browser. It extends from, and has access to all the methods of the Request and Message ...

An upload form is displayed, allowing a user to select a file and upload it. When the form is submitted, the file is uploaded to the destination you specify. Along the way, the file is validated to ...

The Form Helper file contains functions that assist in working with forms.

Please read the upgrade notes corresponding to the version you are upgrading from.