WHMCS upgrade modules addon from 5.3 to 7.1

I have read your project. I'm sure i can help you to do it. I have made many WHMCS modules, such as: + Notify skype when received a ticket. + Integrate VPS manage tools in clientarea: VNC console, firewall control, .... + Get graph (network traffic, hard disk I/O ...) through proxmox . + Calculate, draw chart of transactions. + Integrate domain registrar + Integrate new payment I have 7 years of experience in Web development, System administrator and Security researcher. Choose me then you will work with a Professional Devops, you won't be disappointed. Thanks.