This method checks differences between the versions and applies them.


1)	Download the .diff from: https://magento.com/tech-resources/download under dropdown for version required. (Not all versions have .diff files. Possibly use the .sh new patch file else locate)

2)	Upload the downloaded file to root of Magento installation.

3)	Using terminal/ssh cd to magento root.

4)	Run the command patch -p1 -i  the_downloaded_file_from_step_1_with_extension

5)	Follow prompts in terminal. Using Y for yes.

6)	Check/test patch applied successfully.