diff --git a/package-lock.json b/package-lock.json
index 1e5e28a..85f3ebd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -941,9 +941,9 @@
       }
     },
     "@types/fs-extra": {
-      "version": "9.0.7",
-      "resolved": "https://registry.npmjs.org/@types/fs-extra/-/fs-extra-9.0.7.tgz",
-      "integrity": "sha512-YGq2A6Yc3bldrLUlm17VNWOnUbnEzJ9CMgOeLFtQF3HOCN5lQBO8VyjG00a5acA5NNSM30kHVGp1trZgnVgi1Q==",
+      "version": "9.0.8",
+      "resolved": "https://registry.npmjs.org/@types/fs-extra/-/fs-extra-9.0.8.tgz",
+      "integrity": "sha512-bnlTVTwq03Na7DpWxFJ1dvnORob+Otb8xHyUqUWhqvz/Ksg8+JXPlR52oeMSZ37YEOa5PyccbgUNutiQdi13TA==",
       "dev": true,
       "requires": {
         "@types/node": "*"
@@ -993,9 +993,9 @@
       }
     },
     "@types/node": {
-      "version": "12.20.1",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-12.20.1.tgz",
-      "integrity": "sha512-tCkE96/ZTO+cWbln2xfyvd6ngHLanvVlJ3e5BeirJ3BYI5GbAyubIrmV4JjjugDly5D9fHjOL5MNsqsCnqwW6g==",
+      "version": "14.14.32",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-14.14.32.tgz",
+      "integrity": "sha512-/Ctrftx/zp4m8JOujM5ZhwzlWLx22nbQJiVqz8/zE15gOeEW+uly3FSX4fGFpcfEvFzXcMCJwq9lGVWgyARXhg==",
       "dev": true
     },
     "@types/normalize-package-data": {
@@ -4949,12 +4949,11 @@
       }
     },
     "ts-jest": {
-      "version": "26.5.2",
-      "resolved": "https://registry.npmjs.org/ts-jest/-/ts-jest-26.5.2.tgz",
-      "integrity": "sha512-bwyJ2zJieSugf7RB+o8fgkMeoMVMM2KPDE0UklRLuACxjwJsOrZNo6chrcScmK33YavPSwhARffy8dZx5LJdUQ==",
+      "version": "26.5.3",
+      "resolved": "https://registry.npmjs.org/ts-jest/-/ts-jest-26.5.3.tgz",
+      "integrity": "sha512-nBiiFGNvtujdLryU7MiMQh1iPmnZ/QvOskBbD2kURiI1MwqvxlxNnaAB/z9TbslMqCsSbu5BXvSSQPc5tvHGeA==",
       "dev": true,
       "requires": {
-        "@types/jest": "26.x",
         "bs-logger": "0.x",
         "buffer-from": "1.x",
         "fast-json-stable-stringify": "2.x",
diff --git a/package.json b/package.json
index ec9d653..3697eb4 100644
--- a/package.json
+++ b/package.json
@@ -38,14 +38,15 @@
   },
   "homepage": "https://github.com/Jason-Rev/hunspell-reader#readme",
   "devDependencies": {
-    "@types/fs-extra": "^9.0.7",
-    "@types/node": "^12.20.1",
+    "@types/fs-extra": "^9.0.8",
+    "@types/jest": "^26.0.20",
+    "@types/node": "^14.14.32",
     "cspell": "^5.2.4",
     "jest": "^26.6.3",
     "prettier": "^2.2.1",
     "rimraf": "^3.0.2",
-    "ts-jest": "^26.5.1",
-    "typescript": "^4.1.5"
+    "ts-jest": "^26.5.3",
+    "typescript": "^4.2.3"
   },
   "dependencies": {
     "commander": "^7.1.0",
diff --git a/src/app.ts b/src/app.ts
index c3f26b5..fb214f2 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -15,7 +15,7 @@ const packageInfo = require('../package.json');
 const version = packageInfo['version'];
 
 let displayHelp = true;
-let logStream = process.stderr;
+let logStream: NodeJS.WritableStream = process.stderr;
 
 commander.version(version);
 
@@ -183,7 +183,7 @@ async function actionPrime(hunspellDicFilename: string, options: Options) {
     const callback = showProgress
         ? () => {
               current++;
-              !(current % reportProgressRate) && process.stderr.write(calcProgress(), 'UTF-8');
+              !(current % reportProgressRate) && process.stderr.write(calcProgress(), 'utf-8');
           }
         : () => {};
     const seqWords = transform ? reader.seqAffWords(callback) : reader.seqRootWords().map(asAffWord);