Minimum target sdk policy in Google play . : androiddev

Hello everyone,

As we saw in https://android-developers.googleblog.com/2017/12/improving-app-security-and-performance.html

” 2019 onwards: Each year the targetSdkVersion
requirement will advance. Within one year following each Android dessert release, new apps and app updates will need to target the corresponding API level or higher.”

Does anybody heard about exact dates when and which api level will be the next minimum targetSdk? 27 or 28?
Maybe it was done once (for instance because of security issue in Android) or rather will be repeating every year?