The general procedure to upgrade to a new release:
An upgrade process will run when logging in as admin after upgrading the cart files. During this process, the previous database is backed up into cart_data/database_backups, and any changes to the database are applied.
The upgrade process may sometimes include more or fewer files and directories than those listed above. We will endeavour to detail these at the time of release.
Special Instructions for Upgrading from 2.1.0 to 2.1.1
It is only necessary to replace the application directory. Framework and resources do not require updating.
Special Instructions for Upgrading to 2.1.0
In addition to copying the above-mentioned directories, also:
Should you encounter any issues in upgrading, please visit the CE3 Cart Forum, at http://community.theturninggate.net/forum/28/ttg-ce3-cart/