diff --git a/package.json b/package.json
index 5fa3019a..095ae11d 100644
--- a/package.json
+++ b/package.json
@@ -17,11 +17,11 @@
   "dependencies": {
     "common-tags": "^1.4.0",
     "dlv": "^1.1.0",
-    "eslint": "^4.5.0",
+    "eslint": "^4.0.0",
     "indent-string": "^3.2.0",
     "lodash.merge": "^4.6.0",
     "loglevel-colored-level-prefix": "^1.0.0",
-    "prettier": "^1.9.0",
+    "prettier": "^1.7.0",
     "pretty-format": "^22.0.3",
     "require-relative": "^0.8.7",
     "typescript": "^2.5.1",
diff --git a/src/__tests__/index.js b/src/__tests__/index.js
index 8938a5c6..a6c4e49e 100644
--- a/src/__tests__/index.js
+++ b/src/__tests__/index.js
@@ -351,24 +351,6 @@ test("calls prettier.resolveConfig.sync with the file path", () => {
   expect(prettierMock.resolveConfig.sync).toHaveBeenCalledWith(filePath);
 });
 
-test("does not raise an error if prettier.resolveConfig.sync is not defined", () => {
-  const filePath = require.resolve("../../tests/fixtures/paths/foo.js");
-  const originalPrettierMockResolveConfigSync = prettierMock.resolveConfig.sync;
-  prettierMock.resolveConfig.sync = undefined;
-
-  function callingFormat() {
-    return format({
-      filePath,
-      text: defaultInputText(),
-      eslintConfig: getESLintConfigWithDefaultRules()
-    });
-  }
-
-  expect(callingFormat).not.toThrowError();
-
-  prettierMock.resolveConfig.sync = originalPrettierMockResolveConfigSync;
-});
-
 test("logs if there is a problem making the CLIEngine", () => {
   const error = new Error("fake error");
   eslintMock.CLIEngine.mockImplementation(() => {
diff --git a/src/index.js b/src/index.js
index 764ffa9c..d00f659c 100644
--- a/src/index.js
+++ b/src/index.js
@@ -56,13 +56,13 @@ function format(options) {
   const eslintConfig = merge(
     {},
     options.eslintConfig,
-    getConfig(filePath, eslintPath)
+    getESLintConfig(filePath)
   );
 
   const prettierOptions = merge(
     {},
     filePath && { filepath: filePath },
-    getPrettierConfig(filePath, prettierPath),
+    getPrettierConfig(filePath),
     options.prettierOptions
   );
 
@@ -203,7 +203,7 @@ function getTextFromFilePath(filePath) {
   }
 }
 
-function getConfig(filePath, eslintPath) {
+function getESLintConfig(filePath) {
   const eslintOptions = {};
   if (filePath) {
     eslintOptions.cwd = path.dirname(filePath);
@@ -214,10 +214,10 @@ function getConfig(filePath, eslintPath) {
       "${filePath || process.cwd()}"
     `
   );
-  const configFinder = getESLintCLIEngine(eslintPath, eslintOptions);
+  const cliEngine = getESLintCLIEngine("eslint", eslintOptions);
   try {
     logger.debug(`getting eslint config for file at "${filePath}"`);
-    const config = configFinder.getConfigForFile(filePath);
+    const config = cliEngine.getConfigForFile(filePath);
     logger.trace(
       `eslint config for "${filePath}" received`,
       prettyFormat(config)
@@ -230,14 +230,9 @@ function getConfig(filePath, eslintPath) {
   }
 }
 
-function getPrettierConfig(filePath, prettierPath) {
-  const prettier = requireModule(prettierPath, "prettier");
-
-  // NOTE: Backward-compatibility with old prettier versions (<1.7)
-  //       that don't have ``resolveConfig.sync` method.
-  return typeof prettier.resolveConfig.sync === "undefined"
-    ? {}
-    : prettier.resolveConfig.sync(filePath);
+function getPrettierConfig(filePath) {
+  const prettier = requireModule("prettier", "prettier");
+  return prettier.resolveConfig.sync(filePath);
 }
 
 function requireModule(modulePath, name) {