Beginning with the battery they was drain so fast.
I`ve replaced the battery with a new one.
The same story and I think the new one was broken / bad quality.
Order a new one and replaced it.
The same story.

Than I observate the phone when it`s go so fast down / drain and I see there is a service in the background running it call`s "messageserver" with 91% CPU usage.

The other problem is to activate the developer modus (to get a console/shell) I get a message there are some dependences with the "developer-mode" and I can`t activate.

Is there any other possibility to get an shell ?

How I can fixed the problem with the fast battery drain respective with the high CPU usage comming from "messageserver" (can be) ?

Search in forum developer-mode.
Than install N9QTweak and use BME reset = option B

OK, developer-mode is more a secondarily issue.
My main issue is the battery and now I can say the "messageserver" service is 100% the problem.
For what is this service responsible and how can I preventive this problem ?
The last chance what I see is to reset the complete smartpohne but this means a lot of work for me (it`s the phone from my wife).

Ok. Messageserver can be chat or mail.

Have you a lot of mailaccounts that are checking new mails every 10 minutes? Do you have problems with checking mails on one of these accounts?
What chat-accounts do you use?

Yes, there are two mail account`s installed.
Yes, sometimes there are hanging with the mail check (T-Com, POP3 account).
Chat accounts are Jabber and WhatsApp. Normally they running very well.

Another problem is to install "n9repomirror_0.7.1".
Failure is "Installation unsuccessfully".
I don know why. Do you have any idea ?

I`ve installed now at first the version 0.6. No problem.
After this the updatemanger pop up and has informed me a new version of n9repomirror is now available. I try it but the same story. Failure !

Nevertheless I can activate now the developer-mode, what I think in the first step (but the required packages are not fully installed).
Can be there are some dependences there are not fulfilled.

Yes. I have the same problem. Go with the Browser to openrepos.net, search N9RepoMirror and donwload the old version 0.6. Then install that. 0.6 is working

This is what I`ve done and you are right: It`s working but after this installation when I want to activate the developer-mode the installation of the required packages won`t be fully installed.

New Repos are installed but the developer mode dosn`t work.
It`s a one way !

Facebook also can be the problem. Or a big file on mail or chat that the N9 try to download?

I don`t use Facebook !
I will check the mail client and the messanger services.
Developer-mode dosn`t run !

First install N9Reppomirror (the old version).
Then restart N9
Then install developer-mode have to work