Hello!
We are happy to share that all the courses of the Scala Specialization have now been migrated to Scala 3! The two remaining courses were Big Data Analysis with Scala and Spark and The Scala Capstone Project. The Scala 3 versions should be available in the coming weeks.
The Scala 2 version of the Spark course will still be available here (to be published soon, but at the time of writing the link is not yet available): https://www.coursera.org/learn/scala2-spark-big-data. Note that the Scala 2 version has also been updated (it now uses Scala 2.13 and Spark 3.2).