Steps to upgrade grails version from 3.0.x to 3.3.x

Question

I am looking to upgrade my grails application(3.0.17) to version 3.3.11. Are there any steps that could be followed to upgrade it completely :

1. Should we create a new app (v3.3.11) from scratch and then move our existing app files to this new app(according to new project structure)?
2. Or we can make the upgrade changes in the existing app itself?

Answer 1

Please check out the official docs:

• for upgrading to 3.2.x: https://docs.grails.org/3.2.0/guide/single.html#upgrading31x
• for upgrading from 3.2.x to 3.3.x: https://docs.grails.org/3.3.0/guide/single.html#upgrading

Answer 2

1. Should we create a new app (v3.3.11) from scratch and then move our existing app files to this new app(according to new project structure)?
2. Or we can make the upgrade changes in the existing app itself?

Either will work and if done correctly, both approaches will lead to the exact same code in the project after the upgrade. Having been involved in many many Grails upgrades over the last 13 or so years I can say that creating a new app is a big time saver for a number of reasons. Of course the "new" app code gets put in place of the old code and committed to source code control and from looking at source code history you really shouldn't be able to tell if all the files were written by hand or they were created by create-app and then potentially edited.

I hope that makes sense. Best of luck!