Is it possible to upgrade to higher plan as required?

Hi

Just checking if it's possible to subscribe to bronze level on a monthly basis and then upgrade as required to silver if the demand warrants.

Yes. You can upgrade or downgrade your account as per your requirement. Please be noted that once you downgrade the account, the limits of the plan will be automatically applied to the account. 

Hope this information helps! If you have any other questions, please let us know. We will be happy to help.