Microsoft official said the Anniversary Update will only update the system this year. For 2017 but plans to two new updates.
Windows 10 came in 2015 two updates, codenamed Threshold Threshold 1 and 2. The annual update (code name Redstone 1) is third in the order. According to an article on TECH updates Redstone Redstone 2 and 3 will come next year in spring and autumn.
Although Microsoft said it wants to issue every year two or three updates for Windows 10, it seems that this year the practice diverges with this statement. Of course, in the meantime we can expect classic fixes and security updates via Windows Update.