Has anyone figured out how to install clang-9 on travis? I'm seeing: Adding APT Sources Disallowing sources: llvm-toolchain-xenial-9 See https://travis-ci.org/boostorg/multiprecision/jobs/588146074 With .travis.yml containing: - os: linux env: TOOLSET=clang COMPILER=clang++-9 CXXSTD=c++17 TEST_SUITE=misc addons: apt: packages: - clang-9 - libgmp-dev - libmpfr-dev - libmpc-dev - libmpfi-dev sources: - ubuntu-toolchain-r-test - llvm-toolchain-xenial-9 Which works fine for clang-8. Any ideas anyone? Thanks! John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus