Honor and Profit was announced 2-3 days after Spin#3 was released.
Order and Chaos was accounced 2-3 days after Lunar#2 was released.
Data and Destiny was announced 2-3 days after SanSan#3 was released.
Let me make an educated guess. Since Mumbad#3 was released yesterday, I think the fifth Deluxe expansion will be announced this Saturday or Monday.