Install the PHP IMAP extension

The IMAP extension provides functions for using the IMAP and POP3 protocols.

For PHP 5.6 through PHP 8.3, the IMAP extension is installed by default. You do not need to install the IMAP extension for these PHP versions.

Starting with PHP 8.4, the IMAP extension was removed from PHP and must be installed as a third-party extension using the instructions below.

Install the IMAP extension

Installing the extension involves the following steps:

Install build dependencies (packages that are required to build the extension).
Build the extension’s library file.
Enable the extension in the PHP configuration.

Install build dependencies

Set environment variables for the package manager.

export DEBIAN_FRONTEND=noninteractive

Install a compiler and other packages that are required for building PHP extensions.

sudo apt-get -y install gcc g++ make autoconf libc-dev pkg-config

Install additional packages that are required to build the IMAP extension.

sudo apt-get -y install libkrb5-dev libc-client-dev libssl-dev

Build the extension

The PECL install command compiles the extension’s .so library file.

php8.5
php8.4

yes '' | sudo pecl8.5-sp install imap

yes '' | sudo pecl8.4-sp install imap

Enable the extension

Configure PHP to load the extension.

php8.5
php8.4

sudo bash -c "echo extension=imap.so > /etc/php8.5-sp/conf.d/imap.ini"

sudo bash -c "echo extension=imap.so > /etc/php8.4-sp/conf.d/imap.ini"

Restart PHP-FPM.

php8.5
php8.4

sudo service php8.5-fpm-sp restart

sudo service php8.4-fpm-sp restart

Verify the extension is enabled in PHP.

php8.5
php8.4

php8.5-sp -i | grep imap

php8.4-sp -i | grep imap

If the extension is enabled, you will see output like the following.

/etc/php8.4-sp/conf.d/imap.ini,
Protocols => dict, file, ftp, ftps, gopher, gophers, http, https, imap, imaps, ldap, ldaps, mqtt, pop3, pop3s, rtmp, rtmpe, rtmps, rtmpt, rtmpte, rtmpts, rtsp, scp, sftp, smb, smbs, smtp, smtps, telnet, tftp
imap
imap.enable_insecure_rsh => Off => Off