diff --git a/package.json b/package.json
index 675c8dee..44d2d5f5 100644
--- a/package.json
+++ b/package.json
@@ -43,7 +43,7 @@
     "sinon-chai": "2.9.0",
     "ts-loader": "2.0.3",
     "tslint": "4.5.1",
-    "typescript": "2.2.1",
+    "typescript": "2.1",
     "webpack": "2.3.1"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 4be3cbdc..4dfb01d0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1003,7 +1003,7 @@ engine.io@1.8.3:
     engine.io-parser "1.3.2"
     ws "1.1.2"
 
-enhanced-resolve@^3.0.0, enhanced-resolve@^3.1.0:
+enhanced-resolve@^3.0.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/enhanced-resolve/-/enhanced-resolve-3.1.0.tgz#9f4b626f577245edcf4b2ad83d86e17f4f421dec"
   dependencies:
@@ -2275,14 +2275,10 @@ object-assign-sorted@^2.0.1:
   dependencies:
     sorted-object "^2.0.0"
 
-object-assign@4.1.0:
+object-assign@4.1.0, object-assign@^4.0.1, object-assign@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-4.1.0.tgz#7a3b3d0e98063d43f4c03f2e8ae6cd51a86883a0"
 
-object-assign@^4.0.1, object-assign@^4.1.0, object-assign@^4.1.1:
-  version "4.1.1"
-  resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-4.1.1.tgz#2109adc7965887cfc05cbbd442cac8bfbb360863"
-
 object-component@0.0.3:
   version "0.0.3"
   resolved "https://registry.yarnpkg.com/object-component/-/object-component-0.0.3.tgz#f0c69aa50efc95b866c186f400a33769cb2f1291"
@@ -3301,15 +3297,16 @@ tar@^2.2.1:
     fstream "^1.0.2"
     inherits "2"
 
-text-encoding@0.6.4:
-  version "0.6.4"
-  resolved "https://registry.yarnpkg.com/text-encoding/-/text-encoding-0.6.4.tgz#e399a982257a276dae428bb92845cb71bdc26d19"
 term-size@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/term-size/-/term-size-0.1.1.tgz#87360b96396cab5760963714cda0d0cbeecad9ca"
   dependencies:
     execa "^0.4.0"
 
+text-encoding@0.6.4:
+  version "0.6.4"
+  resolved "https://registry.yarnpkg.com/text-encoding/-/text-encoding-0.6.4.tgz#e399a982257a276dae428bb92845cb71bdc26d19"
+
 through@^2.3.6:
   version "2.3.8"
   resolved "https://registry.yarnpkg.com/through/-/through-2.3.8.tgz#0dd4c9ffaabc357960b1b724115d7e0e86a2e1f5"
@@ -3416,9 +3413,9 @@ type-is@~1.6.14:
     media-typer "0.3.0"
     mime-types "~2.1.13"
 
-typescript@2.2.1:
-  version "2.2.1"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.2.1.tgz#4862b662b988a4c8ff691cc7969622d24db76ae9"
+typescript@2.1:
+  version "2.1.6"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.1.6.tgz#40c7e6e9e5da7961b7718b55505f9cac9487a607"
 
 uglify-js@^2.8.5:
   version "2.8.14"
@@ -3487,11 +3484,7 @@ useragent@^2.1.12:
     lru-cache "2.2.x"
     tmp "0.0.x"
 
-utf8@2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/utf8/-/utf8-2.1.0.tgz#0cfec5c8052d44a23e3aaa908104e8075f95dfd5"
-
-util-deprecate@^1.0.2, util-deprecate@~1.0.1:
+util-deprecate@~1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"