The Ubuntu release team have announced a 1st test ISO RC build for all 18.10 flavours.
Please help us test these and subsequent RC builds, so that we can have an amazing and well tested release in the coming week.
As noted below, the initial builds will NOT be the final ones.
Over the next few hours, builds will start popping on the Cosmic Final milestone page[1] on the ISO tracker. These builds are not final. We're still waiting on a few more fixes, a few things to migrate, etc. I've intentionally not updated base-files or the ISO labels to reflect the release status (so please don't file bugs about those). What there are, however, are "close enough" for people to be testing in anger, filing bugs, fixing bugs, iterating image builds, and testing all over again. So, please, don't wait until Wednesday night to test, testing just before release is TOO LATE to get anything fixed. Get out there, grab your favourite ISO, beat it up, report bugs, escalate bugs, get things fixed, respin (if you're a flavour lead with access), and test, test... And test. Did I mention testing? Please[2] test. Thanks, ... Adam [1] http://iso.qa.ubuntu.com/qatracker/milestones/397/builds [2] Please.
Downloads for RC builds can be found by following the 
link after clicking through to ‘Cosmic Final’ on the Ubuntu ISO tracker. Please report test case results if you have a Ubuntu SSO account (or are prepared to make one). Feedback can also be given via our normal email lists, IRC, forums etc.
Upgrade testing from 18.04 in installed systems (VM or otherwise) is also a very useful way to help prepare for the new release. Instructions for upgrade can be found on the Ubuntu help wiki.
Ubuntu ISO tracker: http://iso.qa.ubuntu.com/qatracker/
Kubuntu-devel mailing list: https://lists.ubuntu.com/mailman/listinfo/kubuntu-devel
Kubuntu IRC channels: #kubuntu & #kubuntu-devel on irc.freenode.net
Kubuntu 18.10 Upgrade instructions: https://help.ubuntu.com/community/CosmicUpgrades/Kubuntu