The Android 10 teaser that appeared in South Korea yesterday has also been spotted in the US and Germany. This was posted through the Samsung Members app.
In the US, unlocked phones as well as those on Sprint and T-Mobile’s network will be able to join the beta test. In Germany, it's going to be open for unlocked phones – this includes the Galaxy S10+, Galaxy S10 and Galaxy S10e. The Galaxy S10 5G is not listed, but according to the teaser from Korea, it will be added later on.
Unfortunately, none of the teasers reveal the start date of the beta testing period. This software update is doubly interesting because in addition to Android 10, it will also bring the sequel to Samsung’s One UI.