Updating Ember-CLI's version and ember project's version are different thing.
To update Ember-CLI:
npm uninstall -g ember-cli
npm cache clean
bower cache clean
npm install -g ember-cli@1.13.14
To update your project:
rm -rf node_modules bower_components dist tmp
npm install --save-dev ember-cli@1.13.14
npm install
bower install
ember init
Here is the resource: https://github.com/ember-cli/ember-cli/releases
I strongly recomend you to select which files will be overwritten. You should compare diffs of files. application.hbs, router.js, environment.js, ember-cli-build.js are important files those you don't want them to be overwritten.
UPDATE 2020-02-19:
ember-cli-update
handles updating your project.