Digital TV (DTV) systems are defined by a set of specifications that establish the technologies involved in the content encoding, transmission, reception and presentation, including the specification of applications (non-linear programs), their various related media objects and metadata. In this scenario, support to applications is accomplished through an intermediary software layer, or middleware, positioned, in the receiving environment, between the application code and the execution infrastructure (hardware platform and operating system). The middleware design and implementation bring a number of challenging issues. Among them are: efficient resource management, since resources are usually scarce in DTV receiver devices; support to dynamic evolution of the middleware functionalities; support to fault recovery at runtime; the mechanisms for resource location management, allowing using the same syntax used in the authoring environment the different receiver environments; support to live editing of nonlinear programs (i.e. applications); the infrastructure definition for the asynchronous transport of interactive applications and control commands; and the life cycle control of interactive applications, allowing applications to be started, paused and resumed at any point in their life duration, without losing their evolution history. Most of these issues are addressed in the existing systems, however with important limitations; some of them are not even addressed, being only treated with workaround tricks. This work proposes alternative solutions to the mentioned issues and incorporates these solutions in the Ginga-NCL declarative middleware specification and in its reference implementation. Ginga- NCL and its declarative NCL language were adopted by SBTVD-T in 2007. In early 2009, Ginga-NCL and NCL have become part of the ISDB-TB standard and part of the ITU-R BT 1699 Recommendation. Even in early 2009, Ginga-NCL and NCL have become the ITU-T H.761 Recommendation for IPTV services.