diff --git a/.swift-version b/.swift-version
new file mode 100644
index 0000000..4d0dcda
--- /dev/null
+++ b/.swift-version
@@ -0,0 +1 @@
+4.1.2
diff --git a/.travis.yml b/.travis.yml
index cc2bf77..cb22438 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,10 +21,26 @@ matrix:
     - os: linux
       dist: trusty
       sudo: required
+      env: SWIFT_SNAPSHOT=4.0.3
+    - os: linux
+      dist: trusty
+      sudo: required
+    - os: linux
+      dist: trusty
+      sudo: required
+      env: SWIFT_SNAPSHOT=swift-4.2-DEVELOPMENT-SNAPSHOT-2018-07-02-a
     - os: osx
       osx_image: xcode9.2
+      sudo: required
+      env: SWIFT_SNAPSHOT=4.0.3
+    - os: osx
+      osx_image: xcode9.4
       env: JAZZY_ELIGIBLE=true
       sudo: required
+    - os: osx
+      osx_image: xcode9.4
+      sudo: required
+      env: SWIFT_SNAPSHOT=swift-4.2-DEVELOPMENT-SNAPSHOT-2018-06-04-a
 
 before_install:
   - git clone https://github.com/IBM-Swift/Package-Builder.git