- uploader downloads hash.xml to compare local version with the one on server, temporarily stores it as oldHash.xml
- uploader uploads new hash.xml to newupdate/hash.xml on server along with update files
- php deployer copies newupdate/hash.xml to root folder during deployment
- launcher downloads it, calling it locally serverHash.xml. It compares serverHash.xml to localHash.xml (that might not exist if it’s being launched for the first time). After update is complete, serverHash.xml is kept as localHash.xml
More or less.