We're considering to upgrade Magento EE to 1.14, now we have 1.12. My question is if we have some webservices to upload the products and stuff with soap v2 it will have some changes? And do you know if is easy or has some complications because I was searching and saw that is an important change from .12 to .14. Is it necessary to do a complete backup of files and database? Thanks for any information.
I'm in the same boat as you, but when I started a year ago, we were on 1.9...
how soap works won't change.
You'll have to upgrade to .13, then .14... and with each change comes more changes to your database, code, and styles. 1.13 changes how indexing, caching and the checkout flow operate... which means you have to make sure all of those still work before continuing onto 1.14, which includes responsive elements.
Yes, it is necessary to do a complete backup of the database and code... by creating a 'snapshot' of your site, you can move it to your development environment and make your changes on that before you roll them live. Saves a lot of time.
A full backup is always recommended during any upgrade attempt. You should also make sure to do the upgrade in a dev/staging system first and test for errors.
The move from EE 1.12 -> 1.13 can be a bit tricky for some (depending on size of stores, etc). There are changes to the way url keys are handled. You need to make sure all of your url keys are unique.
Also, if you are using any kind of reverse proxy cache (nginx, varnish, etc) you will need to take some extra care/precaution due to the addition of form keys.
Any upgrade, big or small should have a full database backup. Files should be held in some kind of version control system so isn't as vital to backup files. Media files should not be effected either.
Soap will remain the same.
Finally it is possible to upgrade from 1.12 to 1.14, we have done this before multple times, however there were major indexer and url changes made during these versions and it would be a slight risk. However all that is happening is additional setup scripts would run all at once. One tool we use is n98-magerun using the incremental setup script run feature. It allows you to run setup scripts 1 at a time addressing any issues as they arise.