Starting late last night (or earlier this morning), our macOS build using the XCode 8.3 image started failing on the Homebrew install package step with the message:
Error: Your Homebrew is outdated. Please run
Our last working build was June 17 @ 10:35ish pm PST: https://travis-ci.org/GMLC-TDC/HELICS-src/jobs/547065289
And our first build seeing the error was June 18 @ 10:25ish am PST: https://travis-ci.org/GMLC-TDC/HELICS-src/jobs/547328813
update: true for updating Homebrew does resolve the error, but it significantly increases the build time by 26 minutes (6 minutes for running brew update, and installing packages takes an extra 20 minutes, probably updating a bunch of other installed packages).