What are the best possible ways to migrate my project developed in ionic beta 13 version to the latest release of ionic beta 14?
I recommend to review the changelog of ionic https://github.com/driftyco/ionic/blob/master/CHANGELOG.md and the migration guide from AngularJS 1.2 to 1.3 (since the underlying AngularJS version was bumped with beta14 of ionic).
The Angular migration guide is located here: https://docs.angularjs.org/guide/migration
For most projects, the two commands that you'd want to use to get Ionic up to date are:
First, make sure your CLI is up to date:
sudo npm install -g ionic
Second, update the project libraries:
ionic lib update
For advanced users, the links shared in other answers will be of great help.