Hi @huangfe001 and welcome to the best community ever!
As you change your subscription from Internet 40 to 100, there is any changement do to. Normally, the modem you have has not to be changed.
However, you will have to pay the 99CHF activation fee if you don’t change your subscritpion via MyUPC. Actually, there is an online bonus. If you change your subscription online, there will be any activation fee to pay!
More infos here : http://community.upc-cablecom.ch/t5/Announcements/Activation-fee-waived/ba-p/82238
If you have other questions, do not hesitate!