Upgrade PHP 5.4 to 5.5 or 5.6

Hello,

how i can Upgrade my PHP 5.4 to 5.5 or 5.6 with a good way. I dont will destroy my Webserver. I have Debian Wheezy 7.8 and I-MSCP 1.2.x Git. I have search in this Forum for a good Tutorial but i dont find a good thing. I have try it with PHPSwitcher but it dont work because i have PHP-FPM.

Thx!

Thx for your help. I can't easy upgrade to debian jessi because i have other programms of the server and i dont know it run of debian 8.
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After Upgrade on 1.2.9 i can use the command "perl imscp-autoinstall -dr httpd"

I have install Phpswitcher and install php 5.5 and 5.6

After i change a PHP Version from a Subdomain my Main Domain dont work.

In logs from my main Domain i see the PHP Version is the same as from the Subdomain but i dont change die Main Domain PHP Version. I see in the logs from my Main Domain:
PHP version: 5.5.24
WCF version: 2.1.8 pl 1 (Typhoon)

In I-MSCP the Main Domain has 5.4.45

the Error because my Main Homepage crash because in the php.ini from 5.5 it is the false Timezone:

[Date]
; Defines the default timezone used by the date functions
; http://php.net/date.timezone
date.timezone = {PHP_TIMEZONE}

in 5.4 is

[Date]
; Defines the default timezone used by the date functions
; http://php.net/date.timezone
date.timezone = Europe/Berlin

Hello,

thank you for your fast looking. How can i update the Phpswitcher after you bring a update ?

i dont find the folder /var/www/imscp/plugins/PhpSwitcher/templates

I only find /var/www/imscp/gui/plugins/PhpSwitcher but in this i dont find a templates folder or file