diff --git a/package.json b/package.json
index 3baf9e6..97bf684 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,10 @@
   "repository": "git@github.com:mcataford/draft-js-commit-log-plugin.git",
   "author": "Marc Cataford <c.marcandre@gmail.com>",
   "license": "MIT",
-  "files": ["src/*.js", "!*.test.js"],
+  "files": [
+    "src/*.js",
+    "!*.test.js"
+  ],
   "scripts": {
     "lint": "eslint ./src",
     "test": "jest ./src"
@@ -30,6 +33,7 @@
     "react-dom": "^16.13.1"
   },
   "dependencies": {
+    "immutable": "^4.0.0-rc.12",
     "uuid": "^7.0.3"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 9f519c7..41364e5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1932,6 +1932,11 @@ ignore@^4.0.6:
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-4.0.6.tgz#750e3db5862087b4737ebac8207ffd1ef27b25fc"
   integrity sha512-cyFDKrqc/YdcWFniJhzI42+AzS+gNwmUzOSFcRCQYwySuBBBy/KjuxWLZ/FHEH6Moq1NizMOBWyTcv8O4OZIMg==
 
+immutable@^4.0.0-rc.12:
+  version "4.0.0-rc.12"
+  resolved "https://registry.yarnpkg.com/immutable/-/immutable-4.0.0-rc.12.tgz#ca59a7e4c19ae8d9bf74a97bdf0f6e2f2a5d0217"
+  integrity sha512-0M2XxkZLx/mi3t8NVwIm1g8nHoEmM9p9UBl/G9k4+hm0kBgOVdMV/B3CY5dQ8qG8qc80NN4gDV4HQv6FTJ5q7A==
+
 immutable@~3.7.4:
   version "3.7.6"
   resolved "https://registry.yarnpkg.com/immutable/-/immutable-3.7.6.tgz#13b4d3cb12befa15482a26fe1b2ebae640071e4b"