[horde] Output issue for “pecl memcache install“ (prerequisite for Horde installation)

[keepshango at free.fr]

*** TEST ENVIRONMENT ***
Machine : remote VPS 2vCore
OS distro : Ubuntu 20.04
Web server : apache 2.4
Cpanel : ISPConfig 3.2.2

 I am blocked at section 5 of the PREREQUISITES (ADDITIONAL PECL
MODULES) to install HORDE GROUPWARE WEBMAIL EDITION.

WHATEVER I ALREADY TRIED (see CHECK-LIST BELOW) as per getting rid of
it, I STILL HAVE THE SAME OUTPUT when executing “PECL MEMCACHE INSTALL“
command line : 

*** OUTPUT ***
 S~# pecl install memcache
 pecl/memcache requires PHP (version >= 8.0.0), installed version is
7.4.15
 No valid packages found 

***************

 I WOULD THEN GREATLY APPRECIATE SOME HELP to solve this issue, starting
with having Horde developpers's opinion upon ANOTHER TRAIL I HAVE IN
MIND (MORE INFO AT THE END OF MY MESSAGE).

 HERE BELOW IS THE CHECK-LIST OF ALL ITEMS THAT I HAVE BEEN INSTALLING
(OR ADDED) TO MY SERVER, IN THE HOPE THAT IT WOULD HELP ! And in
ISPConfig 3.2.2 (my control panel), I ADDITIONALLY changed the RELEVANT
WEBSITE PHP VERSION SETTING FROM DEFAULT TO PHP 8 (e.g.
"groupware.domain-name.net"), as to prepare HGWE installation.

 *** CHECK LIST ***
 This check-list was initially shared in a thread [1] (second-to-last
post) that I opened in the HOWTOFORGE FORUM that is dedicated to linux
and ISPConfig tutorials.

 1) MEMCACHE SERVER (SOURCE [2]) : apt-get install memcached
libmemcached-tools -y
 2) MEMCACHE PHP CLIENT (source [3]): apt-get install apache2
libapache2-mod-php php php-cli php-memcached -y
 3) ONDŘEJ SURÝ PPA REPO (SOURCE [4]) : apt-get install apache2
libapache2-mod-php php php-cli php-memcached -y

 RIGHT BELOW IS ANOTHER TRAIL I HAVE IN MIND, as alternative or
completion to what should be done TO INSTALL MEMCACHE PHP EXTENSION :

 REPLACING “PEUL MEMCACHE INSTALL“ WITH BOTH THE FOLLOWING COMMAND LINES
 (last advice posted on my thread on the Howtoforge forum…) : 

 	* pecl -d php_suffix=8.0 install memcache
 	* pecl uninstall -r memcache

WELL, I NEED SOME HELP, including having other one's opinion upon this
advice.

 Regards, 

Links:
------
[1]
https://www.howtoforge.com/community/threads/php-8-version-set-in-panel-but-terminal-says-its-not-installed.86381/#post-418295
[2]
https://www.howtoforge.com/how-to-install-memcached-on-ubuntu-2004-lts/
[3]
https://www.howtoforge.com/how-to-i...untu-2004-lts/#configure-php-to-use-memcached
[4] https://computingforgeeks.com/how-to-install-php-on-ubuntu-2/