0.13.0 released

Friday, April 07, 2017 | Posted in Release

0.13.0 is a high priority release recommended for all Pony users. #1868 fixes a type system problem identified by Paul LiƩtar. Paul is currently working on verifying the Pony type system as part of his final year project at Imperial College. Expect to see more high priority releases as we fix problems that Paul identifies.

There is also a breaking change in 0.13.0. RFC #41 was implemented and merged to master. The received method on TCPConnectionNotify now takes an additional parameter. For any of your code, if you previously had:

fun ref received(conn: TCPConnection ref, data: Array[U8] iso): Bool

You’ll need to update your method signature to be:

fun ref received(conn: TCPConnection ref, data: Array[U8] iso, times: USize): Bool

It’s safe to ignore the times parameter unless you need more fine-grained control over how a TCPConnection interacts with the Pony scheduler.


  • Do not allow capability subtyping when checking constraint subtyping. (PR #1816)
  • Allow persistent map to use any hash function (PR #1799)


  • Pass # of times called to TCPConnectionNotify.received (PR #1777)


Sean T. Allen

Sean is a member of the Pony core team. His turn-ons include programming languages, distributed computing, Hiwatt amplifiers, and Fender Telecasters. His turn-offs include mayonnaise, stirring yogurt, and sloppy code. He is one of the authors of Storm Applied, and VP of Engineering at Wallaroo Labs.