Let's see the case:
You download an app from the Autodesk App Store : AutoCAD Store: Plugins and Add-ons for AutoCAD | Autodesk App Store
You install the app to your PC. It is working ok with old AutoCAD version: for example, you open AutoCAD 2021 and the app is autoloaded, shows up in in Add-Ins tab.
But when you have new AutoCAD 2023 version, open it, and you don't see the app in the Add-Ins tab.
You check the product page and see AutoCAD 2023 is not supported yet. It is newly released about for a month. The developer hasn't update the app. Or if he has, the Autodesk App Store hasn't done the review to republish the app.
So you drop a message to the developer asking for support: "Please add support for AutoCAD 2023", and wait ...
Even if the developer can solve the problem right away, the Autodesk App Store can't. There are thousand apps pending for review there. It often takes a month to republish a new version of the app.
Luckily, most of time, the issue can be solve quite easily following these steps:
1. Find the applicationplugins folder: it can be either in "C:\Users\...username...\AppData\Roaming\Autodesk\ApplicationPlugins\" folder, or in "C:\ProgramData\Autodesk\ApplicationPlugins\" folder. Rarely happens, but it can be in "C:\Program Files\Autodesk\ApplicationPlugins" folder too, if you can't find it in the above two.
2. Find the [app name].bundle folder: most apps over the store are like that: their app folder's name is "[appname].bundle". Here, you can see my 7cad 3D Unfold's app folder:
3. Open PackageContents.xml file: this is the instruction file for AutoCAD to load the app. If AutoCAD 2023 doesn't find itself in the PackageContents.xml loading instruction, it won't load the app.
4. Therefore, you got to edit the PackageContents.xml. Open it with Notepad, or Notepad++ (recommended)
5. Scroll down and you can see something like this in Notepad:
6. There can be many <Components ...>, but take care about the bottom one only.
7. Find "SeriesMax = 24.1" or something else like "SeriesMax = 24.0". It is the version number. Don't be scared, edit it to "SeriesMax = "R25.0" right away. Then you got the app to be autoloaded to AutoCAD version from SeriesMin = R19.0 to SeriesMax = 25.0, hence, from version 2013 to version 2024. (yeah, not only 2023, but 2024, so you don't have to do it again next year)
8. Don't edit any other things, or you will make the PackageContents.xml unreadable to AutoCAD.
8. Save changes, close the PackageContents.xml, then reopen AutoCAD 2023 to see the effect.
Apps are different to each other, and some apps have special method to load to AutoCAD. But following the above routine, I am sure it will work for most of the apps.