A large family of distributed transactional protocols have a common structure, called Deferred Update Replication (DUR). DUR provides dependability by replicating data, and performance by not re-executing transactions but only applying their updates. Protocols of the DUR family differ only in behaviors of few generic functions. Based on this insight, we offer a generic DUR middleware, called G-DUR, along with a library of finely-optimized plug-in implemen- tations of the required behaviors. This paper presents the middleware, the plugins, and an extensive experimental eval- uation in a geo-replicated environment. Our empirical study shows that:(i) G-DUR allows developers to implement various transactional protocols under 600 lines of code; (ii) It provides a fair, apples-to-apples comparison between transactional protocols; (iii) By replacing plugs-ins, developers can use G-DUR to understand bottlenecks in their protocols; (iv) This in turn enables the improvement of existing proto- cols; and (v) Given a protocol, G-DUR helps evaluate the cost of ensuring various degrees of dependability.