This is probably one of the most important Trotsky texts alongside Permanent Revolution. The codified concept of the transitional demand is meant to achieve a balance between opportunist "minimalist" demands and ultraleft "maximalist" demands, designed to appeal to workers at their current state of consciousness while both pointing in a revolutionary direction and still being economically feasible under capitalism or in a dual power situation. Some of the demands Trotsky included in this 1930s text would probably be considered ultraleft nowadays (e.g. forming workers' councils as a step towards building dual power, something that desperately needed to happen in Spain at the time but not enough) since we're no where near as organized as workers were then, but others probably wouldn't need much updating. The sliding scale of wages/working hours demand is close to evergreen, for example, so long as inflation is constantly eating away at workers' purchasing power (though we shouldn't necessarily use that exact phrasing).