My interpretation is that, Bionic is available, but in beta since it isn’t announced. Time to add them to the matrix!
I am trying to use ‘dist: bionic’, which appears in the build log as ‘Build dist: bionic’. The Xenial image is still used however with the following in the log ‘Release: 16.04’.
@na-g Are you sure you’re looking at the right build log?
In this test project it does start on Bionic:
https://travis-ci.com/Farwaykorse/test_Travis_CMake/jobs/213737431#L18
Can you post a link to your build? It might be an bug.
@Farwaykorse Here is a link to a build: https://travis-ci.com/na-g/rouladen/jobs/213854421#L18
There is now a category
https://travis-ci.community/c/environments/bionic
It is ‘real’ 
I am seeing the same thing as na-g: using dist:bionic just results in a build with dist:xenial.
We are still using travis-ci.org and not travis-ci.com if that matters anything?
Same here
e[0Ktravis_fold:start:system_info
e[0Ke[33;1mBuild system informatione[0m
Build language: rust
Build group: stable
Build dist: bionic
Build id: 121535317
Job id: 221505185
Runtime kernel version: 4.15.0-1028-gcp
travis-build version: 65949ed1e
e[34me[1mBuild image provisioning date and timee[0m
Mon Mar 25 16:52:50 UTC 2019
e[34me[1mOperating System Detailse[0m
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenialThere’s now a dedicated topic for the wrong vm issue: For `dist: bionic`, Xenial VM is used instead