This is a guide on how to upgrade your game.
What does "upgrade" mean?
You've started making your game in a version of Essentials. That's great, but now there's a new version of Essentials out, and you want your game to have the improvements that came in that new version. How are you going to make this happen?
Simple. You're going to start with the latest version of Essentials, and modify it to turn it into your game.
Put simply, it's much easier than the alternative, which is to take the new things from Essentials and put them into your game. The change log for the latest version is just a general overview of what's happened, and doesn't list absolutely everything anyway. You'll end up wasting a whole lot of time figuring out what changes you'd need to copy over, and you'll probably miss some anyway which means you'll break things.
On the other hand, you know exactly what you've done while making your game; you know if you've edited/added any scripts or files (and which ones), you know how you've put your maps and events together, and you've been keeping track of all that specifically for this moment - the tutorial "How to use Essentials" told you to do so.
So you know what you need to do in order to turn a fresh copy of Essentials into your game. So do it.
From here on, "Essentials" refers to a fresh, unaltered copy of the latest version.
You should follow these instructions in order. The first few steps deal with replacing files, which means you do not need to open your game until the "Upgrade scripts" step.
Replace PBS files
This is an easy one. Replace the PBS files in Essentials with the ones from your game.
Occasionally, the structure of a PBS file will have changed in a new version of Essentials in order to make them work better or allow more options. These changes will definitely be listed in the change log, so make sure you read it carefully and see if you'll need to modify anything in your own PBS files.
Replace graphic/audio files
This is also an easy thing to do. Replace any Essentials files with your own.
Again, keep an eye on the change log to see if anything important has happened to the files you're replacing (unlikely). You should also look at the files you're replacing to make sure yours have the correct filenames and show the appropriate thing (e.g. a screen's background).
Replace maps and other data files
Your game's maps and data files are stored in the "Data" folder. Below is a table listing all the data files you need to look at.
||These are your map files ("XXX" is a 3-digit number). Delete these from Essentials and copy across the ones from your game.
Bear in mind, though, that some code used by events may have changed in the new version of Essentials, meaning the events in your maps may need updating. The example maps may demonstrate the new code and how it works, in which case it's worth keeping them as a reference somehow (either in the same project or a separate one).
||This keeps track of your map files. Again, delete it from Essentials and copy your own one over.||Always|
||This contains the names of all Global Switches and Global Variables, as well as some unimportant information. Note that Essentials may change these too, so you'll need to make sure its and your Switches/Variables don't clash, and that you end up with both sets. To make this easy on yourself, start at Switch 51/Variable 26 (i.e. the next blank page after the ones used by Essentials) so that the sets won't overlap. After replacing this file with your own, manually rename the Essentials Switches/Variables to the latest names.||Always, with caution|
||This contains all the information about your Common Events. If you are not using any, you can ignore it, but otherwise you should replace it with your own.||If changed|
||This contains all the information about the tilesets. If you're using your own tilesets rather than the ones Essentials comes with, you should replace this file; otherwise, leave it alone.||If changed|
||These are the animations from the Database and the Essentials Animation Editor respectively. They may have changed in Essentials, so if you have altered/created any animations, you will need to export them from your game and then import them into Essentials.||No, modify|
You can ignore all other files in this folder. When you compile the game, they will be replaced with new versions containing your game's data (i.e. compiled from your PBS files).
Open Essentials in RPG Maker XP and continue reading. You shouldn't have opened it before now.
You will have been keeping track of any changes you've made to the scripts. Now you'll need to find those changes, go through them one by one, and copy them over to Essentials.
This sounds like a big task, and it can be (depending on how many changes you've made), but it's honestly the best method. You can search for the keyword you've used to mark your changes in order to find them easily.
Sometimes some of the scripts in Essentials will have been moved around a bit. You may need to look around in Essentials a bit to find the places to copy your changes into.
Always make sure that your changes are necessary. Essentials might have fixed a bug you've also fixed, so you won't need to do anything there. Again, have a look at the change log to see if you yourself have already done anything listed there.
You should never simply copy the scripts file from your game into Essentials. The scripts are what make Essentials work the way it does, and if you blindly replace them all with your own (based on an older version), then you won't have actually upgraded anything.
Once you have finished replacing everything, the first thing you must do (before you do anything else) is fully compile your game. Do this by running your game from within RPG Maker XP, and holding Ctrl. This will make sure all your data files have been updated to use your game's information.
That's it! The latest version of Essentials has now been turned into your game. Put the old version of your game somewhere safe as a backup, and carry on with your new version.