Installing Drupal

I would be most grateful for advice on migrating a Drupal 7 multisite to a cloud. I have read "Drupal on Google App Engine and AWS". Here is the current profile:

I have several Drupal 7 sites running on my ISP with no problems. I recently tried to install Drupal 8.1.1 in a test. It installed with no problems, and seems to run OK, except the update module can't get the core update information. Here's the error logs:

Hi,

there is one page I want to upgrade, but to not crash existing one I tried to instal its backup on another, testing domain. Everything went fine but... when I try to enter my testpage I'm autoredirected to oldone so I can't even login to testpage. How can I change it? What file is responsible for it?

thanks,
Mark

[SOLVED--See comment below.]

I'm installing Drupal 8.1.1 8.1.2 on a newly configured CentOS 7 server. FWIW, I have installed a lot of Drupal (though often not done much past that!) and fixed a lot of requirement errors but I haven't seen this one before and I'm baffled.

Here's the text:

Unicode library Error
Multibyte string input conversion in PHP is active and must be disabled. Check the php.ini mbstring.http_input setting. Please refer to the PHP mbstring documentation for more information.

Good morning!

I'm trying to install Drupal 7.43 on a shared Linux server. I tried installing an earlier version just in case, and ended up with the same error. After I finish entering the data on the site configuration page of the install script, I get the following error message:

The requested page "/install.php?profile=standard&locale=en" could not be found.

Hi!

Recently I had one of my websites hacked. I took this as an opportunity to read more about security.

I used the security_review module to check for issues on the website and it turned out the web-server had the permission to write to the php files.

Among others, I read this article: https://www.drupal.org/node/244924