Original link: Why We’re Moving to a Source Available License / ScyllaDB blog.
ScyllaDB 6.2 will be the last version with an open source (AGPL) version.
This is their explanation of why.
And for those that don't know ScyllaDB, then it is a reimplementation in C++ of Apache Cassandra which is Java based. And for those that don't know Apache Cassandra, then it is a NoSQL database (wide column data store).