In the hope this can help if some of you encountered the problem below.
I installed the updated version of mobile Joomla (1.2.3)
There was then an issue described as followed (impossibility to reach the component on back office, and all the front office website was corrupted then:)
Call-time pass-by-reference has been removed in /...../...../...../...../plugins/mobile/simple.php on line 225
So I opened the file and this line says originally :
line 224 if(strpos($ua, ' resolution\\') !== false
line 225 && preg_match('# resolution\\(\d{3})(\d{3})\b#', $ua, &$matches))
I changed it like that and everything is working fine and back to normal.
line 224 if(strpos($ua, ' resolution\\') !== false
line 225 && preg_match('# resolution\\(\d{3})(\d{3})\b#', $ua, $matches))
P.S : I'm totally not an expert, so and I don't even know the reason why deleting "&" in front of "$matches" made everything back to normal. In the hope that it hasn't created a new bug that I haven't seen yet, please if you encounter the same problem, post your solution here. If I see a change in the behaviour of the component, I'll come and rewrite a post, for this issue to be followed and fully understood. Anyone who is willing to give any explanation is welcome of course.
Thanks for your support. I've found many useful advices on this forum, thanks to the Mobile Joomla team, and the members. I hope this post might be helpful too.