diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12757d5..ee3eed9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,13 @@ This project does its best to adhere to [Semantic Versioning](http://semver.org/
 
 
 --------
-### [0.8.5](N/A) - 2019-11-08
+### [0.9.0](N/A) - 2020-09-04
+#### Changed
+* Update to TypeScript 4.0
+
+
+--------
+### [0.8.5](https://github.com/TeamworkGuy2/ts-date-times/commit/cbe2914f8c975ba0a7fc5ea487f9ba951b66abea) - 2019-11-08
 #### Changed
 * Update to TypeScript 3.7
 
diff --git a/package.json b/package.json
index 7106909..94b23c5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ts-date-times",
-  "version": "0.8.5",
+  "version": "0.9.0",
   "description": "Manage dates, timestamps, and .NET DateTime JSON in TypeScript",
   "author": "TeamworkGuy2",
   "homepage": "https://github.com/TeamworkGuy2/ts-date-times",
@@ -16,7 +16,7 @@
     "@types/mocha": "~5.2.7",
     "chai": "~4.2.0",
     "mocha": "~5.2.0",
-    "typescript": "~3.7.2"
+    "typescript": "~4.0.2"
   },
   "scripts": {
     "test": "node node_modules/mocha/bin/_mocha -u tdd --recursive",
diff --git a/tsconfig.json b/tsconfig.json
index 852bb57..6443e6c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,7 +5,9 @@
     "lib": [ "es2017" ],
     "module": "commonjs",
     "noEmitOnError": true,
+    "noImplicitAny": true,
     "noImplicitReturns": true,
+    "noImplicitThis": true,
     "removeComments": false,
     "sourceMap": false,
     "strict": true,