diff --git a/lib/ajv.d.ts b/lib/ajv.d.ts
index f42b34800b..cb600e168a 100644
--- a/lib/ajv.d.ts
+++ b/lib/ajv.d.ts
@@ -80,9 +80,9 @@ declare namespace ajv {
     /**
     * Get compiled schema from the instance by `key` or `ref`.
     * @param  {string} keyRef `key` that was passed to `addSchema` or full schema reference (`schema.id` or resolved id).
-    * @return {Function} schema validating function (with property `schema`).
+    * @return {Function} schema validating function (with property `schema`). Returns undefined if keyRef can't be resolved to an existing schema.
     */
-    getSchema(keyRef: string): ValidateFunction;
+    getSchema(keyRef: string): ValidateFunction | undefined;
     /**
     * Remove cached schema(s).
     * If no parameter is passed all schemas but meta-schemas are removed.
@@ -169,7 +169,7 @@ declare namespace ajv {
     jsonPointers?: boolean;
     uniqueItems?: boolean;
     unicode?: boolean;
-    format?: string;
+    format?: false | string;
     formats?: object;
     keywords?: object;
     unknownFormats?: true | string[] | 'ignore';
diff --git a/package.json b/package.json
index 6f15e2dd0f..5cfec97d2b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ajv",
-  "version": "6.10.2",
+  "version": "6.11.0",
   "description": "Another JSON Schema Validator",
   "main": "lib/ajv.js",
   "typings": "lib/ajv.d.ts",
@@ -25,7 +25,7 @@
     "build": "del-cli lib/dotjs/*.js \"!lib/dotjs/index.js\" && node scripts/compile-dots.js",
     "test-karma": "karma start",
     "test-browser": "del-cli .browser && npm run bundle && scripts/prepare-tests && npm run test-karma",
-    "test-all": "npm run test-ts && npm run test-cov && if-node-version 10 npm run test-browser",
+    "test-all": "npm run test-cov && if-node-version 10 npm run test-browser",
     "test": "npm run lint && npm run build && npm run test-all",
     "prepublish": "npm run build && npm run bundle",
     "watch": "watch \"npm run build\" ./lib/dot"
@@ -87,8 +87,8 @@
     "karma-chrome-launcher": "^3.0.0",
     "karma-mocha": "^1.1.1",
     "karma-sauce-launcher": "^2.0.0",
-    "mocha": "^6.0.0",
-    "nyc": "^14.0.0",
+    "mocha": "^7.0.1",
+    "nyc": "^15.0.0",
     "pre-commit": "^1.1.1",
     "require-globify": "^1.3.0",
     "typescript": "^2.8.3",