The advent of LED lighting and in particular LED downlights, have been popular for retro fitting to replace existing tungsten fittings that require canisters to limit the heat transfer that will occur in the roof space. Most of these older style fittings have outlived their use by dates and it is a natural progression to upgrade.
Most LED downlights have in-built drivers and are fitted with a 3 pin plug top and flexible lead, so require a socket base fixed to the roofing structure. When selecting the fitting, you should be aware that the rules for installing recessed luminaires are subject to clause 18.104.22.168 Lamps near flammable materials.
Using IC-4 luminaires is a good option in most cases as these fittings can be abutted against normally flammable materials, including building insulation, and can be covered in normal use. Building elements, building insulation or debris have restricted access to the heated parts of the luminaire. This classification of recessed luminaire is effectively a sealed unit that has a restricted flow of air between the habitable room the luminaire emits light into and the void/space where the main body of the luminaire is located.
IC-4 luminaires complying with AS/NZS 60598.2.2 are marked with the symbol shown in Figure 4.16.