Upgrading Drupal

So I have two sites with drupal 8 commerce one which is my main site, and the other which had an install in a subdirectory, and a third with just a basic install with a few modules like admin toolbar.

I was able to update the subdirectory installation flawlessly had no other modules in it. When I attempted to update the root installation i got server error 500. At first I thought it was my configuration and or htaccess file. I could not get this error

I have updated the drupal core to 7.41 . when i am updating the modules manually i run into error

PHP Fatal error: Class 'DrupalDefaultEntityController' not found in ...

i have tried fixing the error by rebuilding the repositories using Registry_rebuild
and also tried with drush .

when are try using with update.php method, it gives another error saying An AJAX HTTP error occurred. HTTP Result Code: 500 Debugging .

Hi all,
I have drupal version 7.25 and i want upgrade to 7.41 in my control panel.
When i go to Available updates in my control panel it show me Manual updates required.
how can i Manual updates drupal?

Dear All,

Good day!

Hi, i installed d8 rc1 and now with the rc2 i thought that would be the first time i could update core easily..
But no, it is still the same as in d7, need to upload all files again..
Is it how it will be in d8?
I thought with d8 we would have passed that point which is a pain compared to wordpress which does it easily for a long time.

Asking this question here because it's being asked of me -- what are everyone's best practices for timeliness when updating Drupal 7.x core, i.e., how soon after a minor release are you performing a production upgrade? I'm getting some pushback on the potential twice-monthly frequency of core updates as being problematic, even though no official objections have been raised, and our elapsed downtime for any update is usually on the order of 5-7 minutes, on a website that, while necessary, is not "critical" in terms of availability.