diff --git a/yarn.lock b/yarn.lock
index 05ba9e9..a2d3b69 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -37,7 +37,7 @@
     "@platzi/markdown" "1.0.1"
     prop-types "^15.5.4"
 
-abab@^1.0.3:
+abab@1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/abab/-/abab-1.0.3.tgz#b81de5f7274ec4e756d797cd834f303642724e5d"
 
@@ -1462,7 +1462,7 @@ expand-range@^1.8.1:
   dependencies:
     fill-range "^2.1.0"
 
-express@^4.15.2:
+express@4.15.2:
   version "4.15.2"
   resolved "https://registry.yarnpkg.com/express/-/express-4.15.2.tgz#af107fc148504457f2dca9a6f2571d7129b97b35"
   dependencies:
@@ -1880,7 +1880,7 @@ ignore-by-default@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/ignore-by-default/-/ignore-by-default-1.0.1.tgz#48ca6d72f6c6a3af00a9ad4ae6876be3889e2b09"
 
-immutable@^3.8.1:
+immutable@3.8.1:
   version "3.8.1"
   resolved "https://registry.yarnpkg.com/immutable/-/immutable-3.8.1.tgz#200807f11ab0f72710ea485542de088075f68cd2"
 
@@ -2079,7 +2079,7 @@ isobject@^2.0.0:
   dependencies:
     isarray "1.0.0"
 
-isomorphic-fetch@^2.1.1, isomorphic-fetch@^2.2.1:
+isomorphic-fetch@2.2.1, isomorphic-fetch@^2.1.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/isomorphic-fetch/-/isomorphic-fetch-2.2.1.tgz#611ae1acf14f5e81f729507472819fe9733558a9"
   dependencies:
@@ -2297,7 +2297,7 @@ lowercase-keys@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/lowercase-keys/-/lowercase-keys-1.0.0.tgz#4e3366b39e7f5457e35f1324bdf6f88d0bfc7306"
 
-lru-cache@^4.0.1, lru-cache@^4.0.2:
+lru-cache@4.0.2, lru-cache@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-4.0.2.tgz#1d17679c069cda5d040991a09dbc2c0db377e55e"
   dependencies:
@@ -2619,7 +2619,7 @@ node-pre-gyp@^0.6.29:
     tar "^2.2.1"
     tar-pack "^3.4.0"
 
-nodemon@^1.11.0:
+nodemon@1.11.0:
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/nodemon/-/nodemon-1.11.0.tgz#226c562bd2a7b13d3d7518b49ad4828a3623d06c"
   dependencies:
@@ -3013,7 +3013,7 @@ react-deep-force-update@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/react-deep-force-update/-/react-deep-force-update-2.0.1.tgz#4f7f6c12c3e7de42f345992a3c518236fa1ecad3"
 
-react-dom@^15.5.4:
+react-dom@15.5.4:
   version "15.5.4"
   resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-15.5.4.tgz#ba0c28786fd52ed7e4f2135fe0288d462aef93da"
   dependencies:
@@ -3039,7 +3039,7 @@ react-proxy@^3.0.0-alpha.0:
   dependencies:
     lodash "^4.6.1"
 
-react@^15.5.4:
+react@15.5.4:
   version "15.5.4"
   resolved "https://registry.yarnpkg.com/react/-/react-15.5.4.tgz#fa83eb01506ab237cdc1c8c3b1cea8de012bf047"
   dependencies:
@@ -3239,8 +3239,8 @@ semver-diff@^2.0.0:
     semver "^5.0.3"
 
 "semver@2 || 3 || 4 || 5", semver@^5.0.3, semver@^5.3.0:
-  version "5.3.0"
-  resolved "https://registry.yarnpkg.com/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
+  version "5.7.2"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.7.2.tgz#48d55db737c3287cd4835e17fa13feace1c41ef8"
 
 send@0.15.1:
   version "0.15.1"