ubuntu - PHP ignores one "additional INI file" (imap)

I need help in understanding an issue. My problem: After upgrading Ubuntu 12 LTS to 14 LTS, the function imap_open() is unavailable in PHP/FPM. Well, nothing strange so far, here's the info from the php_info():

Loaded Configuration File   /etc/php5/fpm/php.ini
Scan this dir for additional .ini files     /etc/php5/fpm/conf.d
Additional .ini files parsed    /etc/php5/fpm/conf.d/05-opcache.ini, /etc/php5/fpm/conf.d/10-pdo.ini, /etc/php5/fpm/conf.d/20-apcu.ini, /etc/php5/fpm/conf.d/20-curl.ini, /etc/php5/fpm/conf.d/20-gd.ini, /etc/php5/fpm/conf.d/20-json.ini, /etc/php5/fpm/conf.d/20-mysql.ini, /etc/php5/fpm/conf.d/20-mysqli.ini, /etc/php5/fpm/conf.d/20-pdo_mysql.ini, /etc/php5/fpm/conf.d/20-readline.ini 
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No need to search for: There is no*-imap.ini in the list. But ...

$ ls -l /etc/php5/fpm/conf.d
lrwxrwxrwx 1 root root 32 Aug  2 22:20 05-opcache.ini -> ../../mods-available/opcache.ini
lrwxrwxrwx 1 root root 28 Aug  2 22:20 10-pdo.ini -> ../../mods-available/pdo.ini
lrwxrwxrwx 1 root root 29 Aug  2 22:20 20-apcu.ini -> ../../mods-available/apcu.ini
lrwxrwxrwx 1 root root 29 Aug  2 22:26 20-curl.ini -> ../../mods-available/curl.ini
lrwxrwxrwx 1 root root 27 Aug  2 22:26 20-gd.ini -> ../../mods-available/gd.ini
lrwxrwxrwx 1 root root 29 Aug  3 23:18 20-imap.ini -> ../../mods-available/imap.ini
lrwxrwxrwx 1 root root 29 Aug  2 22:20 20-json.ini -> ../../mods-available/json.ini
lrwxrwxrwx 1 root root 31 Aug  2 22:20 20-mysqli.ini -> ../../mods-available/mysqli.ini
lrwxrwxrwx 1 root root 30 Aug  2 22:20 20-mysql.ini -> ../../mods-available/mysql.ini
lrwxrwxrwx 1 root root 34 Aug  2 22:20 20-pdo_mysql.ini -> ../../mods-available/pdo_mysql.ini
lrwxrwxrwx 1 root root 33 Aug  2 22:26 20-readline.ini -> ../../mods-available/readline.ini
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... there shall be! And the only information I find in /var/log/php5-fpm.log

[02-Aug-2014 22:33:12] NOTICE: configuration file /etc/php5/fpm/php-fpm.conf test is successful
[03-Aug-2014 05:55:43] NOTICE: configuration file /etc/php5/fpm/php-fpm.conf test is successful
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Where am I missing something? Thanks for any hints!