Spark: When is the next version due for release?

Yesterday, I was about to purchase Laravel Spark when I saw this message:

Licenses are valid for an entire major release "series". In other words, a license entitles you to all updates until the next series release. That current series is Spark Aurelius (initially released February 2018) and includes Spark 6.0+. New series are released roughly once every two years.

I did a Twitter-search for Laravel Spark but couldn't find much useful about a release schedule for a new version, other than Taylor once replying "This fall" to a comment.

Is there any way to find an official statement on when the next version of Spark is due for release, other than reading through random Twitter threads? I'd hate to purchase a licence now, only to have a new series released in two weeks.