Required Salesforce Version
You will need a Salesforce license that includes all APIs (BULK, REST and STREAMING APIs), therefore Salesforce Enterprise Edition or better is required.
See editions here ( https://www.salesforce.com/editions-pricing/sales-cloud/).
FrontSpin uses the Bulk API for the initial sync, Rest API for periodic sync (which runs every 15 minutes) and Streaming API for real-time sync.
If you do not have a Salesforce license yet, you may request a trial from them (just make sure they give you Enterprise Edition with all APIs enabled).