To add, this update process is only applicable for manual update.
Normally, updates can be done via wordpress plugins or update page.
To further elaborate the steps
1) download the zip file from github. name of the file is wp-erp-develop.zip.
2) download the erp folder from the product website. name of the file is erp.zip
3) extract both zip files into their respective folders
4) copy the vendor folder in the erp extracted to the wp-erp-develop extracted folder. this will be the main folder to be used for the updated wp-erp deployment
5) open the wordpress server hosting wp-erp and go to plugins
6) deactivate WP ERP plugin
7) go to htdocs > wp-content > plugins folder
8) check for the wp-erp folder there (can be wp-erp / erp / wp-erp-develop)
9) move all its contents onto an isolated folder
10) transfer the contents of #4 onto the wp-erp folder in #8
11) refresh the plugins page of wordpress
12) activate the wp-erp plugin