diff --git a/.travis.yml b/.travis.yml
index 68494472a..6c26b52fe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,49 +15,34 @@ cache:
   directories:
   - $HOME/.ccache
 
-dist: trusty
-sudo: false
+dist: xenial
 
 matrix:
   include:
     - os: linux
-      name: Linux gcc-6
+      name: Linux clang
       env: >-
-          CXX="ccache g++-6"
-          CC="gcc-6"
-      addons:
-        postgresql: "9.5"
-        apt:
-          sources: [ 'ubuntu-toolchain-r-test']
-          packages: [ 'libstdc++-6-dev', 'g++-6', 'xutils-dev', 'postgresql-9.5-postgis-2.3' ]
-    - os: linux
-      name: Linux clang-3.9
-      env: >-
-          CXX="ccache clang++-3.9 -Qunused-arguments"
-          CC="clang-3.9"
-          ENABLE_GLIBC_WORKAROUND=true
-      before_install:
-        - export LINKFLAGS="-fuse-ld=gold-2.26"
+          CXX="ccache clang++ -Qunused-arguments"
+          CC="clang"
       addons:
         postgresql: "9.5"
         apt:
           sources: [ 'ubuntu-toolchain-r-test' ]
-          packages: [ 'clang-3.9', 'libstdc++-4.9-dev', 'xutils-dev', 'postgresql-9.5-postgis-2.3' ]
+          packages: [ 'xutils-dev', 'postgresql-9.5-postgis-2.4' ]
     - os: linux
-      name: Linux clang-3.9 + coverage
+      name: Linux clang + coverage
       env: >-
-          CXX="ccache clang++-3.9 -Qunused-arguments"
-          CC="clang-3.9"
+          CXX="ccache clang++ -Qunused-arguments"
+          CC="clang"
           COVERAGE=true
           QUIET=true
       before_install:
-        - export LINKFLAGS="-fuse-ld=gold-2.26"
-        - export LLVM_COV="llvm-cov-3.9"
+        - export LLVM_COV="llvm-cov"
       addons:
         postgresql: "9.5"
         apt:
           sources: [ 'ubuntu-toolchain-r-test' ]
-          packages: [ 'clang-3.9', 'llvm-3.9', 'libstdc++-4.9-dev', 'xutils-dev', 'postgresql-9.5-postgis-2.3' ]
+          packages: [ 'xutils-dev', 'postgresql-9.5-postgis-2.4' ]
     - os: osx
       name: OSX clang
       # https://docs.travis-ci.com/user/languages/objective-c/#Supported-OS-X-iOS-SDK-versions
diff --git a/INSTALL.md b/INSTALL.md
index b701a7dc9..4ef4a2124 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -184,7 +184,7 @@ If you need help or want to participate starting points include:
 ### Cartographers
 
 TileMill, which uses Mapnik internally, offers great step by step tutorials for
-learning advanced map styling: http://mapbox.com/tilemill/docs/crashcourse/introduction/
+learning advanced map styling: https://tilemill-project.github.io/tilemill/docs/crashcourse/introduction/
 
 ### Programmers
 
diff --git a/bootstrap.sh b/bootstrap.sh
index 24706b8be..5071d7e74 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -8,7 +8,7 @@ todo
 - shrink icu data
 '
 
-MASON_VERSION="cce4ebf4"
+MASON_VERSION="fde1d9f5"
 
 function setup_mason() {
     if [[ ! -d ./.mason ]]; then
@@ -44,7 +44,7 @@ function install() {
 }
 
 ICU_VERSION="57.1"
-BOOST_VERSION="1.74.0"
+BOOST_VERSION="1.73.0"
 
 function install_mason_deps() {
     install ccache 3.3.1