diff --git a/.travis.yml b/.travis.yml
index d1e3ba8..88939f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
 language: dart
 
 dart:
- - 2.0.0
+ - 2.1.1
  - dev
 
 dart_task:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14334c5..7ed6bc6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.10.11-dev
+
+* Update minimum SDK constraint to version 2.1.1.
+
 ## 0.10.10
 
 * Fix `Int64` parsing to throw `FormatException` on an empty string or single
diff --git a/analysis_options.yaml b/analysis_options.yaml
index 6cd5230..6ddb107 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -1,4 +1,7 @@
 include: package:pedantic/analysis_options.yaml
+analyzer:
+  strong-mode:
+    implicit-casts: false
 linter:
   rules:
     #- annotate_overrides
diff --git a/lib/src/int32.dart b/lib/src/int32.dart
index f3cc72c..3a9d017 100644
--- a/lib/src/int32.dart
+++ b/lib/src/int32.dart
@@ -61,7 +61,7 @@
       if (digit < 0 || digit >= radix) {
         throw FormatException("Non-radix code unit: $c");
       }
-      x = (x * radix) + digit;
+      x = ((x * radix) + digit) as Int32;
     }
     return x;
   }
@@ -189,7 +189,7 @@
       Int64 t = this.toInt64();
       return (t - (t ~/ other) * other).toInt32();
     }
-    return this - (this ~/ other) * other;
+    return (this - (this ~/ other) * other) as Int32;
   }
 
   Int32 operator &(other) {
diff --git a/pubspec.yaml b/pubspec.yaml
index 25e3f70..5864bc1 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,13 +1,13 @@
 name: fixnum
-version: 0.10.10
+version: 0.10.11-dev
 
 description: Library for 32- and 64-bit signed fixed-width integers.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/fixnum
 
 environment:
-  sdk: '>=2.0.0 <3.0.0'
+  sdk: '>=2.1.1 <3.0.0'
 
 dev_dependencies:
-  pedantic: ^1.3.0
+  pedantic: ^1.8.0
   test: ^1.2.0
diff --git a/test/int32_test.dart b/test/int32_test.dart
index 52764b6..b9ba31a 100644
--- a/test/int32_test.dart
+++ b/test/int32_test.dart
@@ -115,15 +115,15 @@
 
     test("remainder", () {
       expect(Int32(0x12345678).remainder(Int32(0x22)),
-          Int32(0x12345678.remainder(0x22)));
+          Int32(0x12345678.remainder(0x22) as int));
       expect(Int32(0x12345678).remainder(Int32(-0x22)),
-          Int32(0x12345678.remainder(-0x22)));
+          Int32(0x12345678.remainder(-0x22) as int));
       expect(Int32(-0x12345678).remainder(Int32(-0x22)),
-          Int32(-0x12345678.remainder(-0x22)));
+          Int32(-0x12345678.remainder(-0x22) as int));
       expect(Int32(-0x12345678).remainder(Int32(0x22)),
-          Int32(-0x12345678.remainder(0x22)));
+          Int32(-0x12345678.remainder(0x22) as int));
       expect(Int32(0x12345678).remainder(Int64(0x22)),
-          Int32(0x12345678.remainder(0x22)));
+          Int32(0x12345678.remainder(0x22) as int));
       expect(() => Int32(17).remainder(null), throwsArgumentError);
     });
 
diff --git a/test/int64_test.dart b/test/int64_test.dart
index 9c9e7ba..1acc3a4 100644
--- a/test/int64_test.dart
+++ b/test/int64_test.dart
@@ -264,15 +264,15 @@
       expect(Int64.MAX_VALUE % Int64.fromInts(0x04000000, 0x00000000),
           Int64.fromInts(0x3ffffff, 0xffffffff));
       expect(Int64(0x12345678).remainder(Int64(0x22)),
-          Int64(0x12345678.remainder(0x22)));
+          Int64(0x12345678.remainder(0x22) as int));
       expect(Int64(0x12345678).remainder(Int64(-0x22)),
-          Int64(0x12345678.remainder(-0x22)));
+          Int64(0x12345678.remainder(-0x22) as int));
       expect(Int64(-0x12345678).remainder(Int64(-0x22)),
-          Int64(-0x12345678.remainder(-0x22)));
+          Int64(-0x12345678.remainder(-0x22) as int));
       expect(Int64(-0x12345678).remainder(Int64(0x22)),
-          Int64(-0x12345678.remainder(0x22)));
+          Int64(-0x12345678.remainder(0x22) as int));
       expect(Int32(0x12345678).remainder(Int64(0x22)),
-          Int64(0x12345678.remainder(0x22)));
+          Int64(0x12345678.remainder(0x22) as int));
       argumentErrorTest("%", (a, b) => a % b);
     });