Drupal updates can be very different. Some of them -- easy patches that you just roll out and forget. Some of them -- break your site. Tricky part is you never know how updates will behave on your site until you actually tried them out.

This is why it is very tricky to give estimates to clients how long it is going to take. They usually do not appreciate answer 1 to 20 hours depending on some random facts.

We all know that Symfony is already in the core of Drupal 8 but how it works and how both systems work? Not that many people understand fully this integration. Me neither but I would like to pubilsh my research notes about how Drupal 8 works now. Surely this material is based on the snapshot of beginning September and I really hope that more things will happen so this information is relevant only for some time.

I don't have any real life experience of the building projects with Symfony so my knowledge is very close to majority of drupal developers.

So lets start.