Before updating, make sure you read the change logs and are aware of potential backward compatibility issues.
Migrating to v1.3 from v1.2.x
Most likely, the migration will not be straight-forward, due to the multiple modifications that were brought to this version. Do not install the update on a production site. Your personal files will not be removed and, as long as you created your own theme files, all your styles will be safe. Core template files will be updated, deprecated files will be removed.
Before updating the template, create a copy of the template's directory (
templates/sywbareresponsive), this will help you pinpoint the differences once the new version is installed.