Why is the old version of the module being used? I am creating a module, and I tried to update its files. I disabled the module, uninstalled it, deleted its files and then I put the new files in the sites/all/modules/mymodule. Then, I enabled my module. 

The problem is that Drupal somehow is using the old version of my module rather than the new files I added. I cleared all the caches, from Drupal and manual from MySQL, but nothing changed.

Anyone ever had the same issue? Any ideas?
When this has happened to me, it's because I have had the module in two locations and forgotten about it. Just search for the module's info file (using for example find - on Linux): 

find /path/to/drupal_root -name mymodule.info