Old Testament prophets majored on the themes of God's coming judgment and future blessing. They often blended the near future with events that were so far distant they have yet to happen. Zephaniah was one of those prophets.
Zephaniah prophesied during King Josiah's reign over Judah, around 625-635 B.C. His messages focused on God's judgments on Judah, fulfilled when Babylon conquered the nation and carried most of the people into exile, and their restoration as a nation. Plus he spoke about the coming "day of the Lord," which is also a still-future time when God will judge the heathen nations and usher in the messianic kingdom of peace and blessing.
Even though it was written over 2,600 years ago, Zephaniah's book is relevant to our times. He warned people of God's judgment on sins like materialism and injustice that are prevalent today. But he also offered hope of a better time to come, a message we also need to hear.