Always backup your existing theme, espically if you have made any modifications to the files as they will be overridden.
Read this to find out how best to update an existing modified theme:
Modifying a Theme Package
Block Templates added
Blocks > Pages List > Blog Thumbnail
Blocks > Date Navigation
CSS Edits
Block styles have been moved out of main.css and added into their relevant folder to make it more modular.
Foundation.css has been tidied up as many of the styles were redundant. This also fixes clashes between some some styles found in Foundation.css and Concrete5's standard stylesheet, which were apparent in Edit Mode.