No defined dates. Base system itself looks OK with 3.17.x kernel, what I have to check a bit the wireelss part. Core extensions in repo already updated or will be updated, so I expect around Xmas time a Release Candidate will be available.
Anyhow my kind advice to use now piCore 6.0 beta line as updates, bug fixes, new repo additions happen with 6.0 while no activity with 5.x, and current version is stable enough to use.
Regarding MONO it is just building. Only 7 hours gone, no idea how long it will run. The good point is that it build with nop errors still. I will let you know when it is finished and ready for testing.
Béla