In later years, the style of stamp messages continued, differing from those of the Stalin times. They were no longer brief imperative commands but rather promises and explanations by the Party to Soviet society. For example, on a 1971 souvenir sheet from the 24th Party Congress series designed by Yu. Levinovsky and A. Shmidshtein, there was an inscription saying that "the main problem is to provide a significant increase of the material and cultural level of life of the people on the basis of high rates of development of socialist production, an increase of its effectiveness, scientific-technical progress, and an acceleration of the growth of the productiveness of labor".