diff --git a/package.json b/package.json
index 8639a1e..d286f87 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
     "sinon": "^7.2.2",
     "ts-node": "^8.0.2",
     "tslib": "^1.9.3",
-    "typescript": "^3.2.2"
+    "typescript": "3.8.3"
   },
   "engines": {
     "node": ">=8.0.0"
diff --git a/src/types.ts b/src/types.ts
index 3f3d2b2..c1f5860 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -20,7 +20,7 @@ export interface Plugin<I> {
 }
 
 export interface PluginDef {
-  output: object;
+  output: object | unknown;
   args: any[];
 }
 
diff --git a/yarn.lock b/yarn.lock
index 483d07f..e16590d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1700,10 +1700,10 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@^3.2.2:
-  version "3.7.5"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.7.5.tgz#0692e21f65fd4108b9330238aac11dd2e177a1ae"
-  integrity sha512-/P5lkRXkWHNAbcJIiHPfRoKqyd7bsyCma1hZNUGfn20qm64T6ZBlrzprymeu918H+mB/0rIg2gGK/BXkhhYgBw==
+typescript@3.8.3:
+  version "3.8.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.8.3.tgz#409eb8544ea0335711205869ec458ab109ee1061"
+  integrity sha512-MYlEfn5VrLNsgudQTVJeNaQFUAI7DkhnOjdpAp4T+ku1TfQClewlbSuTVHiA+8skNBgaf02TL/kLOvig4y3G8w==
 
 underscore.string@~2.4.0:
   version "2.4.0"