Directly to 3.0.3 is fine, just make sure to note the upgrading to 3.0 documentation and understand it is a major upgrade. 3.0 has breaking changes, and not everything is compatible.
Some general advice:
- Do not upgrade to 3.0 directly on production. Upgrade on a staging or development environment.
- Check the compatibility of extras you’re using. Upgrade to the latest version offered to you on 2.x before upgrading, and then check again after upgrading to 3.0 to see if there are specific 3.0-compatible versions.
- If you encounter issues with the upgrade, track down whatever error message you can find (browsers’ developer console, MODX error log, PHP/server error log), and create a forum topic for it. We can help resolve problems for you, but also for others who may encounter it in the future. With everyone that does this, we can make the upgrade easier.
If you have the site connected to SiteDash, make sure to check its “MODX 3 Upgrade” tab which will run a bunch of automatic checks and immediately tell you which installed extras are confirmed to be or compatible or not from the list mentioned above.