Load and Export Player Prefs

How do I export player prefs, the save data in my game so if I release a newer build, version, the players can load there saves. My idea is to use special ID Codes e.g. 01043576532 which people get when they press save data. Then when they go load data they are asked to enter in the ID Code, which will unlock certain Player Prefs. The downside is I will have many levels so it will be close to impossible to do every single code for every different possibilities of unlocked levels e.g. Level 8 and Level 2 Finished, Level 13 Level 6 Level 2 Finished....

What is the easiest way of exporting and Loading Data whether that be a special installer program or a code which analyses what prefs complete and outputs an ID. Help will be appreciated. -Thanks