PHP Warning: PHP Startup: imap: Unable to initialize module (SOLVED). How to install the imap module for PHP on Arch Linux
April 8, 2023
When running a PHP script in Arch Linux or derivative distributions (Manjaro, BlackArch) on the command line:
php 8.php
You may see the following warning from PHP:
PHP Warning: PHP Startup: imap: Unable to initialize module Module compiled with module API=20210902 PHP compiled with module API=20220829 These options need to match in Unknown on line 0 Warning: PHP Startup: imap: Unable to initialize module Module compiled with module API=20210902 PHP compiled with module API=20220829 These options need to match in Unknown on line 0
The message says that the imap module cannot be initialized.
The functions of the imap module allow you to work with the IMAP protocol, as well as NNTP, POP3, and local mailbox access methods. However, be aware that some IMAP features will not work correctly with POP. Also keep in mind that the IMAP module is not thread safe; it should not be used with ZTS builds.
As stated in the PHP documentation, https://www.php.net/manual/en/imap.installation.php, to support imap in PHP, PHP must be compiled with the --with-imap[=DIR] option. But in fact, to enable the imap module on Linux, it is usually enough to install the appropriate package (for example, php8.2-imap) and enable the module as an extension in php.ini.
In Arch Linux, everything worked similarly until the release of PHP 8.2. As stated in the official post https://archlinux.org/news/php-82-update-and-introduction-of-legacy-branch/ the imap extension has been removed from the repository because it relies on the c-client library which has been abandoned a lot of years ago.
On Debian and derivative distributions (Kali Linux, Ubuntu), this does not prevent you from having the php8.2-imap extension in the standard repositories.
There are two options for getting out of this situation in Arch Linux:
- Disable imap extension
- Install the imap extension for PHP 8.2 and later
Let's consider both of these solutions.
How to disable imap extension in PHP on Arch Linux
If you are not using the imap module, then you just need to disable it – it's quite simple.
Open the /etc/php/php.ini file:
sudo gedit /etc/php/php.ini
find the line there
extension=imap
and comment it out to get:
;extension=imap
All is ready! Immediately after that, the warning about the impossibility of initializing the imap module will disappear.
How to install imap extension for PHP on Arch Linux (php82-imap module for Arch Linux)
The AUR has an imap extension for various PHP versions, for example:
- php82-imap
- php81-imap
- php80-imap
For details on how to install packages from the AUR, see the article:
For example:
pikaur -S php82-imap
But it is recommended to go to the extension page https://aur.archlinux.org/packages/php82-imap and read the pinned comment. The author of the extension has created a repository at build.opensuse.org with binaries. You can add this repository to the package sources on your system and install (and update when new versions are released) imap, as well as other extensions for different versions of PHP.
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