If I produce Newspeak [boot images](https://bitbucket.org/newspeaklanguage/nsboot) from the [201801252341 Mac VMs](https://github.com/OpenSmalltalk/opensmalltalk-vm/releases/tag/201801252341), these images do not bring up the UI when subsequently opened, either by the new VMs or old VMs. The new VMs are able to properly bring up images produced by old VMs.
(Maybe there's some new headlessness property in the image header?)