Note: as of 0.10, release notes are available on each release in GitHub - https://github.com/functional-streams-for-scala/fs2/releases

0.9.6

Empty deflated streams are now handled properly #865
concurrent.join now fails when outer stream terminated #869

0.9.5

Fixed memory leak in concurrent.join where up to maxOpen streams that had finished executing were kept in memory until the end of the outer stream was reached. #834
Fixed a bug in fs2.io.JavaInputOutputStream, ensuring bytes are converted to 0-255 before being returned.
Added pipe2.pause and Stream#pause combinators -- similar to interrupt but allows the stream to be resumed.
Added Stream#evalScan - a variant of scan where the supplied function returns an effectful value.
Added pipe.unNone and Stream#unNone, which converts a Stream[F, Option[A]] to a Stream[F, A], ignoring any None values.

0.9.4

Fixed memory leak in Stream#runFoldScope introduced by #808.
Added OSGi metadata to the core and io JARs.

0.9.3

Fixed memory leak in Signal#discrete. #799
Significant performance improvements, especially in map-heavy streams. #776 #784
Fixed bug in runFold which resulted in finalizers being skipped if stream used uncons at root without a scope. #808.
Improved TCP socket buffer management - read buffer is shared now instead of being allocated on each socket read. #809
Added >> to Stream.
Added head to Stream and pipe.
Added unfoldChunk and unfoldChunkEval to Stream.
Added fromAttempt to Task.

0.9.2

Fixed a bug where traversing a list or vector evaluated effects in reverse order. #746
Fixed to and tov so that the output of the sink is not drained. #754
Fixed a bug in Task.Ref where a set after an access set did not result in no-op. #749
Added groupBy to Stream and Pipe.

0.9.1

Fixed bug where a stream with a map or flatMap after an onError would result in the error handler not getting run. #735

0.9.0

First release of new design.