Test on oldest supported SDK, bump SDK to 2.1.0
diff --git a/.travis.yml b/.travis.yml
index 3b66d0d..36eb960 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,14 +14,10 @@
 
 dart:
   - dev
-  - stable
+  - 2.1.0
 
 with_content_shell: false
 
-matrix:
-  allow_failures:
-    - dart: dev
-
 before_install:
   - export CHROMEDRIVER_BINARY=/usr/bin/google-chrome
   - export CHROMEDRIVER_ARGS=--no-sandbox
diff --git a/CHANGELOG.md b/CHANGELOG.md
index da69420..87bb5ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 2.0.2
 
 - Support the latest `package:stream_channel`.
+- Require Dart SDK `>=2.1.0 <3.0.0`.
 
 ## 2.0.1
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 67bdd66..7f4b948 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -8,7 +8,7 @@
   requests.
 
 environment:
-  sdk: ">=2.0.0-dev.64.1 <3.0.0"
+  sdk: ">=2.1.0 <3.0.0"
 
 dependencies:
   async: ^2.0.8