diff --git a/Gruntfile.coffee b/Gruntfile.coffee
deleted file mode 100644
index e01d66d..0000000
--- a/Gruntfile.coffee
+++ /dev/null
@@ -1,38 +0,0 @@
-module.exports = (grunt) ->
-  grunt.initConfig
-    pkg: grunt.file.readJSON('package.json')
-
-    coffee:
-      glob_to_multiple:
-        expand: true
-        cwd: 'src'
-        src: ['*.coffee']
-        dest: 'lib'
-        ext: '.js'
-
-    coffeelint:
-      options:
-        no_empty_param_list:
-          level: 'error'
-        max_line_length:
-          level: 'ignore'
-
-      src: ['src/*.coffee']
-      test: ['spec/*.coffee']
-
-    shell:
-      test:
-        command: 'node node_modules/jasmine-focused/bin/jasmine-focused --captureExceptions --coffee spec'
-        options:
-          stdout: true
-          stderr: true
-          failOnError: true
-
-  grunt.loadNpmTasks('grunt-contrib-coffee')
-  grunt.loadNpmTasks('grunt-shell')
-  grunt.loadNpmTasks('grunt-coffeelint')
-
-  grunt.registerTask 'clean', -> require('fs-plus').removeSync('lib')
-  grunt.registerTask('lint', ['coffeelint:src', 'coffeelint:test'])
-  grunt.registerTask('default', ['coffeelint', 'coffee'])
-  grunt.registerTask('test', ['default', 'coffeelint:test', 'shell:test'])
diff --git a/package.json b/package.json
index 24cb667..347210e 100644
--- a/package.json
+++ b/package.json
@@ -4,8 +4,11 @@
   "description": "Less compile cache",
   "main": "./lib/less-cache",
   "scripts": {
-    "prepublish": "grunt clean lint coffee",
-    "test": "grunt test"
+    "clean": "shx rm -rf lib",
+    "test": "jasmine-focused --captureExceptions --coffee spec",
+    "coffee": "npm run clean && shx cp -r src lib && coffee -c -M -o lib lib && shx rm -rf lib/*.coffee",
+    "build": "npm run coffee",
+    "prepare": "npm run build"
   },
   "repository": {
     "type": "git",
@@ -27,20 +30,18 @@
     }
   ],
   "dependencies": {
-    "fs-plus": "^3.0.0",
-    "less": "^2.7.1",
-    "underscore-plus": "1.x",
-    "walkdir": "0.0.11"
+    "fs-plus": "^3.1.1",
+    "less": "^3.12.2",
+    "underscore-plus": "^1.7.0",
+    "walkdir": "^0.4.1"
   },
   "devDependencies": {
-    "fstream": "^1.0.10",
-    "grunt": "^1.0.1",
-    "grunt-cli": "^1.2.0",
-    "grunt-coffeelint": "0.0.16",
-    "grunt-contrib-coffee": "^1.0.0",
-    "grunt-shell": "^1.3.0",
-    "jasmine-focused": "1.x",
-    "temp": "^0.8.3",
-    "tmp": "0.0.28"
+    "coffeescript": "^1.12.7",
+    "fstream": "^1.0.12",
+    "jasmine-focused": "^1",
+    "temp": "^0.9.1",
+    "tmp": "0.2.1",
+    "shx": "^0.3.2",
+    "cross-env": "^7.0.2"
   }
 }
diff --git a/src/less-cache.coffee b/src/less-cache.coffee
index b6c8555..8714373 100644
--- a/src/less-cache.coffee
+++ b/src/less-cache.coffee
@@ -3,8 +3,8 @@ crypto = require 'crypto'
 
 _ = require 'underscore-plus'
 fs = require 'fs-plus'
-less = null # Defer until it is actually used
-lessFs = null # Defer until it is actually used
+less = require('less') # Defer until it is actually used
+lessFs = less.fs # Defer until it is actually used
 walkdir = require('walkdir').sync
 
 cacheVersion = 1
@@ -105,32 +105,6 @@ class LessCache
     @importedFiles = importedFiles
     @importPaths = importPaths
 
-  observeImportedFilePaths: (callback) ->
-    importedPaths = []
-    lessFs ?= require 'less/lib/less-node/fs.js'
-    originalFsReadFileSync = lessFs.readFileSync
-    lessFs.readFileSync = (filePath, args...) =>
-      relativeFilePath = @relativize(@resourcePath, filePath) if @resourcePath
-      lessSource = @lessSourcesByRelativeFilePath[relativeFilePath]
-      content = null
-      digest = null
-      if lessSource?
-        content = lessSource.content
-        digest = lessSource.digest
-      else
-        content = originalFsReadFileSync(filePath, args...)
-        digest = LessCache.digestForContent(content)
-
-      importedPaths.push({path: relativeFilePath ? filePath, digest: digest})
-      content
-
-    try
-      callback()
-    finally
-      lessFs.readFileSync = originalFsReadFileSync
-
-    importedPaths
-
   readJson: (filePath) -> JSON.parse(fs.readFileSync(filePath))
 
   writeJson: (filePath, object) -> fs.writeFileSync(filePath, JSON.stringify(object))
@@ -194,15 +168,37 @@ class LessCache
       @writeJson(@getCachePath(@importsFallbackDir, filePath), cacheEntry)
 
   parseLess: (filePath, contents) ->
+    entryPath = filePath.replace(/[^\/\\]*$/, '')
+
+    # https://github.com/less/less.js/blob/ef4baa5bb27b932623eb9afede99b3e2aaccea20/packages/less/src/less/contexts.js#L18
+    options = {syncImport: true, paths: @importPaths}
+    context = new less.contexts.Parse(options)
+
+    # https://github.com/less/less.js/blob/ef4baa5bb27b932623eb9afede99b3e2aaccea20/packages/less/src/less/import-manager.js#L9
+    rootFileInfo = {
+      filename: filePath,
+      rootpath: '',
+      currentDirectory: entryPath,
+      entryPath: entryPath,
+      rootFilename: filePath
+    }
+    importManager = new less.ImportManager(less, context, rootFileInfo)
+
     css = null
-    options = filename: filePath, syncImport: true, paths: @importPaths
-    less ?= require('less')
-    imports = @observeImportedFilePaths ->
-      less.render contents, options, (error, result) ->
-        if error?
-          throw error
-        else
-          {css} = result
+    parser = new less.Parser(context, importManager, rootFileInfo)
+
+    parser.parse contents, (err, rootNode) ->
+      if err?
+        throw error
+      else
+        parserTree = new less.ParseTree(rootNode, importManager)
+        {css} = parserTree.toCSS(options)
+
+    imports = []
+    for filename, content of importManager.contents
+      if filename isnt filePath
+        imports.push({path: filename, digest: LessCache.digestForContent(content)})
+
     {imports, css}
 
   # Read the Less file at the current path and return either the cached CSS or the newly