Enabling enhanced durability for bucket

Our team are new to couchbase so apologies for what might be an easy question.
We are using couchbase v5.0 and would like to take advantage of the enhanced durability functionality, we are particularly interested in getting a Mutation Token from each update as it will allow us to replicate our updates in our SQL db.
When we call upsert function the Mutation Token we get back contains -1.
In the client configuration we have set the EnableAdvanceDurability property to true, but I can see that the Connection property SupportsEnhancedDurability is false.
From looking at the code I can see that some server configuration needs updating, but we are not sure how to do this.
Could anyone offer any guidance.